Benzothiophene derivatives as estrogen receptor inhibitors

ABSTRACT

A compound of formula (I): 
     
       
         
         
             
             
         
       
     
     or a pharmaceutically acceptable salt thereof, compositions, combinations and medicaments containing said compounds and processes for their preparation. The invention also relates to the use of said compounds, combinations, compositions and medicaments, for example as inhibitors of the activity of the estrogen receptor, including degrading the estrogen receptor, the treatment of diseases and conditions mediated by the estrogen receptor,

FIELD OF THE INVENTION

The present invention relates to compounds, compositions, combinations and medicaments containing said compounds and processes for their preparation. The invention also relates to the use of said compounds, combinations, compositions and medicaments, for example as inhibitors of the activity of the estrogen receptor, including degrading the estrogen receptor, the treatment of diseases and conditions mediated by the estrogen receptor, in particular for the treatment of breast cancer.

BACKGROUND OF THE INVENTION

The estrogen receptor (ER) is a member of the nuclear hormone receptor family and functions as a ligand-activated transcription factor involved with the up and down regulation of gene expression. The natural hormone for the estrogen receptor is B17-estradiol (E2) and closely related metabolites. Binding of estradiol to the estrogen receptor causes a dimerization of the receptor and the dimer in turn binds to estrogen response elements (ERE's) on DNA. The ERDNA complex recruits other transcription factors responsible for the transcription of DNA downstream from the ERE into mRNA which is eventually translated into protein. Alternatively the interaction of ER with DNA may be indirect through the intermediacy of other transcription factors, most notably fos and jun. Since the expression of a large number of genes is regulated by the estrogen receptor and since the estrogen receptor is expressed in many cell types, modulation of the estrogen receptor through binding of either natural hormones or synthetic ER ligands can have profound effects on the physiology and pathophysiology of the organism.

A variety of diseases have their aetiology and/or pathology mediated by the ER. Collectively these diseases are called estrogen-dependent diseases. Estrogens are critical for sexual development in females. In addition, estrogens play an important role in maintaining bone density, regulation of blood lipid levels, and appear to have neuroprotective effects. Consequently decreased estrogen production in post-menopausal women is associated with a number of diseases such as osteoporosis, atherosclerosis, depression and cognitive disorders. Conversely certain types of proliferative diseases such as breast and uterine cancer and endometriosis are stimulated by estrogens and therefore antiestrogens (i.e. estrogen antagonists) have utility in the prevention and treatment of these types of disorders.

There are two different forms of the estrogen receptor, usually referred to as α and β, each encoded by a separate gene (ESR1 and ESR2, respectively).

Both ERs are widely expressed in different tissue types, however there are some notable differences in their expression patterns. The ERα is found in endometrium, breast cancer cells, ovarian stroma cells, and the hypothalamus. In males, ERα protein is found in the epithelium of the efferent ducts. The expression of the ERβ protein has been documented in kidney, brain, bone, heart, lungs, intestinal mucosa, prostate, and endothelial cells. Development therefore of selective ligands may therefore preserve the beneficial aspects of estrogen.

Breast Cancer is the most common malignancy to affect women and worldwide, the incidence of the disease is increasing. Estrogens, in particular, act as endocrine growth factors for at least one-third of breast cancers, and depriving the tumour of this stimulus is a recognised therapy for advanced disease In premenopausal women, this is achieved by the ablation of ovarian function through surgical, radiotherapeutic, or medical means and, in postmenopausal women, by the use of aromatase inhibitors.

An alternative approach to estrogen withdrawal is to antagonise estrogen with antiestrogens. These are drugs that bind to and compete for estrogen receptors (ER) present in estrogen-responsive tissue. Conventional nonsteroidal antiestrogens, such as tamoxifen, compete efficiently for ER binding but their effectiveness is often limited by the partial agonism they display, which results in an incomplete blockade of estrogen-mediated activity. A specific or “pure” antiestrogen with high affinity for ER and without any agonist effects, may have advantages over conventional nonsteroidal anti estrogens in the treatment of estrogen-dependent disease. Fulvestrant is the first of a new class of potent pure anti estrogens and is completely free of the partial agonist, estrogen-like activity, associated with currently available antiestrogens like tamoxifen.

It would be desirable to investigate other approaches to antagonise the ER receptor.

One approach would be to develop selective ER down regulators or degraders that reduce ER expression at either the transcript or protein level.

Several methods are available for the manipulation of protein levels, including proteolysis targeting chimeric molecules (PROTACs) which contain a ligand that recognizes the target protein linked to a ligand that binds to a specific E3 ubiquitin ligase. It would be desirable to have a small molecule which can simultaneously bind ER and an E3 ubiquitin ligase and which promotes ubiquitination of ER and leads to degradation of ER by the Proteosome. One suitable E3 ubiquitin ligase is the von Hippel-Lindau tumour suppressor (VHL).

The present inventors have identified compounds which are capable of inhibiting estrogen receptor function including compounds which degrade the estrogen receptor.

SUMMARY OF THE INVENTION

In one aspect there is provided a compound of formula (I):

Wherein R¹ is OH, OC₁₋₃alkyl, halogen, H R₂ is OH, OC₁₋₃alkyl

X is O, CO

L is a linking group comprising a length of 8-16 atoms in shortest length R₃ is straight chin or branched C₁₋₆alkyl, C₃₋₆ cycloalkyl R₄ is 4-methylthiazol-5-yl, oxazol-5-yl, halo or a pharmaceutically acceptable salt thereof.

In a further aspect of the present invention, there is provided a compound of formula (I), or a pharmaceutically acceptable salt thereof for use in therapy, in particular in the treatment of diseases and conditions mediated by the estrogen receptor.

In a further aspect of the present invention, there is provided a pharmaceutical composition comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and one or more of pharmaceutically acceptable carriers, diluents and excipients.

In a further aspect of the present invention, there is provided a method of treating diseases and conditions mediated by the estrogen receptor in a subject comprising administering a therapeutically effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof.

In a further aspect of the present invention, there is provided the use of a compound of formula (I), or a pharmaceutically acceptable salt thereof in the manufacture of a medicament for use in treating diseases and conditions mediated by the estrogen receptor.

In a further aspect there is provided a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent.

In a further aspect there is provided a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent for use in therapy, particularly for treating diseases and conditions mediated by the estrogen receptor.

In a further aspect of the invention there is provided a combination comprising compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent for use in treating diseases and conditions mediated by the estrogen receptor.

In a further aspect there is provided a method of treating diseases and conditions mediated by the estrogen receptor comprising administering to a human in need thereof a therapeutically effective amount of a combination comprising compound of formula (I) or a pharmaceutically acceptable salt thereof, and at least one further therapeutic agent.

In a further aspect there is provided the use of a combination comprising compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent in the manufacture of a medicament for treating diseases and conditions mediated by the estrogen receptor.

In a further aspect there is provided a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one anti-neoplastic agent.

In a further aspect there is provided a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one anti-neoplastic agent, for use in therapy, in particular for diseases and conditions mediated by the estrogen receptor.

In a further aspect there is provided a combination comprising a compound of formula (I) or pharmaceutically acceptable salt thereof and at least one anti-neoplastic agent, for use in treating diseases and conditions mediated by the estrogen receptor.

In a further aspect there is provided the use of a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one anti-neoplastic agent, in the manufacture of a medicament for treating diseases and conditions mediated by the estrogen receptor.

In a further aspect there is provided a method of treating diseases and conditions mediated by the estrogen receptor, comprising administering to a human in need thereof a therapeutically effective amount of a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one anti-neoplastic agent.

In a further aspect there is provided a pharmaceutical composition comprising a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof and at least one further therapeutic agent, particularly at least one anti-neoplastic agent and one or more of pharmaceutically acceptable carriers, diluents and excipients.

In a further aspect there is provided a method of degrading the estrogen receptor comprising administration comprising administering to a human in need thereof a therapeutically effective amount of a compound of Formula (I) or a pharmaceutically acceptable salt thereof.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, “a compound of the invention” includes all solvates, complexes, polymorphs, radiolabelled derivatives, stereoisomers and optical isomers of the compounds of formula (I) and salts thereof.

As used herein “halo” means fluoro (—F), chloro (—Cl), bromo (—Br) or iodo (—I).

As used herein, the term “effective amount” means that amount of a drug or pharmaceutical agent that will elicit the biological or medical response of a tissue, system, animal or human that is being sought, for instance, by a researcher or clinician. Furthermore, the term “therapeutically effective amount” means any amount which, as compared to a corresponding subject who has not received such amount, results in improved treatment, healing, prevention, or amelioration of a disease, disorder, or side effect, or a decrease in the rate of advancement of a disease or disorder. The term also includes within its scope amounts effective to enhance normal physiological function.

As used herein, the term “pharmaceutically acceptable” refers to those compounds, materials, compositions, and dosage forms which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, or other problem or complication, commensurate with a reasonable benefit/risk ratio.

The compounds of the invention may exist in solid or liquid form. In solid form, compound of the invention may exist in a continuum of solid states ranging from fully amorphous to fully crystalline. The term ‘amorphous’ refers to a state in which the material lacks long range order at the molecular level and, depending upon the temperature, may exhibit the physical properties of a solid or a liquid. Typically such materials do not give distinctive X-ray diffraction patterns and, while exhibiting the properties of a solid, are more formally described as a liquid. Upon heating, a change from solid to liquid properties occurs which is characterized by a change of state, typically second order (‘glass transition’). The term ‘crystalline’ refers to a solid phase in which the material has a regular ordered internal structure at the molecular level and gives a distinctive X-ray diffraction pattern with defined peaks. Such materials when heated sufficiently will also exhibit the properties of a liquid, but the change from solid to liquid is characterized by a phase change, typically first order (‘melting point’).

The compound of formula (I) may exist in solvated and unsolvated forms. As used herein, the term “solvate” refers to a complex of variable stoichiometry formed by a solute (in this invention, a compound of formula (I) or a salt) and a solvent. Such solvents for the purpose of the invention may not interfere with the biological activity of the solute. The skilled artisan will appreciate that pharmaceutically acceptable solvates may be formed for crystalline compounds wherein solvent molecules are incorporated into the crystalline lattice during crystallization. The incorporated solvent molecules may be water molecules or non-aqueous such as ethanol, isopropanol, DMSO, acetic acid, ethanolamine, and ethyl acetate molecules. Crystalline lattice incorporated with water molecules are typically referred to as “hydrates”. Hydrates include stoichiometric hydrates as well as compositions containing variable amounts of water. The present invention includes all such solvates.

The compounds of the invention may have the ability to crystallize in more than one form, a characteristic, which is known as polymorphism, and it is understood that such polymorphic forms (“polymorphs”) are within the scope of the invention. Polymorphism generally can occur as a response to changes in temperature or pressure or both and can also result from variations in the crystallization process. Polymorphs can be distinguished by various physical characteristics known in the art such as x-ray diffraction patterns, solubility and melting point.

It is also noted that the compounds of formula (I) may form tautomers. It is understood that all tautomers and mixtures of tautomers of the compounds of the present invention are included within the scope of the compounds of the present invention.

As used herein, the term “estrogen receptor inhibitor”, or “inhibitor” refers to any compound or treatment capable of inhibiting or reducing the expression or activity of the estrogen receptor. The inhibitor is preferably selective.

In one aspect R₄ is 4-methylthiazol-5-yl, oxazol-5-yl. In one aspect R₄ is 4-methylthiazol-5-yl; In one aspect R₄ is chloro; In one aspect R₄ is oxazol-5-yl; In one aspect R¹ is OH, F, Br, OCH₃ or H; In a further aspect R¹ is OH; In one aspect R² is OH or OCH₃; In one aspect R² is OH; In one aspect the linker group is a straight chain alkylene group of 8-16 carbon atoms wherein one or more carbon atoms are replaced by a group each independently selected from —O—, —NH—, —N(CH₃)—,

In one aspect the linker group is of formula (ii)

—(R⁵CH₂CH₂)_(X)OCH₂   (ii)

Wherein each R⁵ is independently selected from —O—, —NH—, —N(CH₃)— or

and x is 2-4 In one aspect each R⁵ is O; In a further aspect the linker is selected from (OCH₂CH₂)₄OCH₂ (OCH₂CH₂)₃OCH₂ (OCH₂CH₂)₂OCH₂

OCH₂CH₂N(CH₃)CH₂CH₂OCH₂CH₂OCH₂

OCH₂CH₂N(CH₃)(CH₂)₃(OCH₂CH₂)₂OCH₂

While aspects for each variable have generally been listed above separately for each variable this invention includes those compounds in which several or each aspect in formula (I) is selected from each of the aspects listed above. Therefore, this invention is intended to include all combinations of aspects for each variable.

Examples of compounds of the prevent invention include the following:

-   (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-((6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide -   (2S,4R)-4-Hydroxy-1-((S)-14-(4-((6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)-2-isopropyl-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide -   (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-((6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(oxazol-5-yl)benzyl)pyrrolidine-2-carboxamide -   (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-((2-(4-hydroxyphenyl)-6-methoxybenzo[b]thiophen-3-yl)oxy)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide -   (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-((6-hydroxy-2-phenylbenzo[b]thiophen-3-yl)oxy)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-1-((S)-14-(4-((2-(4-Bromophenyl)-6-hydroxybenzo[b]thiophen-3-yl)oxy)phenoxy)-2-(tert-butyl)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-((2-(4-fluorophenyl)-6-hydroxybenzo[b]thiophen-3-yl)oxy)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-4-Hydroxy-1-((S)-14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-2-methyl-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-1-((S)-2-Ethyl-14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-4-Hydroxy-1-((S)-14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-2-isopropyl-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-1-((S)-2-Cyclopropyl-14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-1-((S)-2-Cyclopentyl-14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-4-Hydroxy-1-((S)-14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-2-isobutyl-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-4-Hydroxy-1-((S)-17-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-2-isopropyl-4-oxo-6,9,12,15-tetraoxa-3-azaheptadecan-1-oyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-1-((S)-2-(tert-Butyl)-17-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12,15-tetraoxa-3-azaheptadecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-(2-(4-Hydroxyphenyl)-6-methoxybenzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-(6-hydroxy-2-(4-methoxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-1-((S)-2-(tert-Butyl)-17-(4-(6-hydroxy-2-(4-methoxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12,15-tetraoxa-3-azaheptadecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(oxazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-4-Hydroxy-1-((S)-2-(2-(2-(2-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethoxy)ethoxy)acetamido)-3,3-dimethylbutanoyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-12-methyl-4-oxo-6,9-dioxa-3,12-diazatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-1-((S)-2-(tert-Butyl)-18-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-16-methyl-4-oxo-6,9,12-trioxa-3,16-diazaoctadecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-4-Hydroxy-1-((S)-2-(2-(2-(2-(4-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)piperazin-1-yl)ethoxy)ethoxy)acetamido)-3,3-dimethylbutanoyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-4-Hydroxy-1-((S)-2-(2-(2-(4-(2-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethyl)piperazin-1-yl)ethoxy)acetamido)-3,3-dimethylbutanoyl)-N-(4-(4-methylthiazol-5-yl)benzyl)     pyrrolidine-2-carboxamide; -   (2S,4R)-4-Hydroxy-1-((S)-2-(2-(4-(1-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)piperidin-4-yl)piperazin-1-yl)acetamido)-3,3-dimethylbutanoyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-4-Hydroxy-1-((S)-2-(2-(9-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)-3,9-diazaspiro[5.5]undecan-3-yl)acetamido)-3,3-dimethylbutanoyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-4-Hydroxy-1-((S)-2-(2-(2-(9-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)-3,9-diazaspiro[5.5]undecan-3-yl)ethoxy)acetamido)-3,3-dimethylbutanoyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-1-((S)-2-(tert-Butyl)-17-(4-(2-(4-hydroxyphenyl)-6-methoxybenzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12,15-tetraoxa-3-azaheptadecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; -   (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-((6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-N-(4-chlorobenzyl)-4-hydroxypyrrolidine-2-carboxamide     and pharmaceutically acceptable salt thereof.

The compounds of Formula (I) may be in the form of a salt. Typically, the salts of the present invention are pharmaceutically acceptable salts. Salts encompassed within the term “pharmaceutically acceptable salts” refer to non-toxic salts of the compounds of this invention. For a review on suitable salts see Berge et al, J. Pharm. Sci. 1977, 66, 1-19.

Suitable pharmaceutically acceptable salts can include acid addition salts. A pharmaceutically acceptable acid addition salt can be formed by reaction of a compound of formula (I) with a suitable inorganic or organic acid (such as hydrobromic, hydrochloric, sulfuric, nitric, phosphoric, p-toluenesulfonic, benzenesulfonic, methanesulfonic, ethanesulfonic, naphthalenesulfonic such as 2-naphthalenesulfonic), optionally in a suitable solvent such as an organic solvent, to give the salt which is usually isolated for example by crystallisation and filtration. A pharmaceutically acceptable acid addition salt of a compound of formula (I) can comprise or be for example a hydrobromide, hydrochloride, sulfate, nitrate, phosphate, p-toluenesulfonate, benzenesulfonate, methanesulfonate, ethanesulfonate, naphthalenesulfonate (e.g. 2-naphthalenesulfonate) salt.

Other non-pharmaceutically acceptable salts, e.g. trifluoroacetates, may be used, for example in the isolation of compounds of the invention, and are included within the scope of this invention.

The invention includes within its scope all possible stoichiometric and non-stoichiometric forms of the compounds of formula (I).

While it is possible that, for use in therapy, the compound of the invention may be administered as the raw chemical, it is possible to present the active ingredient as a pharmaceutical composition. Accordingly, the invention further provides pharmaceutical compositions comprising a compound of the invention and one or more pharmaceutically acceptable carriers, diluents, or excipients. The carrier(s), diluents(s) or excipient(s) must be acceptable in the sense of being compatible with the other ingredients of the composition and not deleterious to the recipient thereof. In accordance with another aspect of the invention there is also provided a process for the preparation of a pharmaceutical composition including the agent, or pharmaceutically acceptable salts thereof, with one or more pharmaceutically acceptable carriers, diluents or excipients. The pharmaceutical composition can be for use in the treatment and/or prophylaxis of any of the conditions described herein.

Pharmaceutical compositions may be presented in unit dose forms containing a predetermined amount of active ingredient per unit dose. Preferred unit dosage compositions are those containing a daily dose or sub-dose, or an appropriate fraction thereof, of an active ingredient. Such unit doses may therefore be administered once or more than once a day. Such pharmaceutical compositions may be prepared by any of the methods well known in the pharmacy art.

Pharmaceutical compositions may be adapted for administration by any appropriate route, for example by the oral (including buccal or sublingual), rectal, inhaled, intranasal, topical (including buccal, sublingual or transdermal), vaginal or parenteral (including subcutaneous, intramuscular, intravenous or intradermal) route. Such compositions may be prepared by any method known in the art of pharmacy, for example by bringing into association the active ingredient with the carrier(s) or excipient(s).

Pharmaceutical compositions adapted for oral administration may be presented as discrete units such as capsules or tablets; powders or granules; solutions or suspensions in aqueous or non-aqueous liquids; edible foams or whips; or oil-in-water liquid emulsions or water-in-oil liquid emulsions.

For instance, for oral administration in the form of a tablet or capsule, the active drug component can be combined with an oral, non-toxic pharmaceutically acceptable inert carrier such as ethanol, glycerol, water and the like. Powders are prepared by reducing the compound to a suitable fine size and mixing with a similarly prepared pharmaceutical carrier such as an edible carbohydrate, as, for example, starch or mannitol. Flavouring, preservative, dispersing and colouring agent can also be present.

Capsules are made by preparing a powder mixture, as described above, and filling formed gelatin sheaths. Glidants and lubricants such as colloidal silica, talc, magnesium stearate, calcium stearate or solid polyethylene glycol can be added to the powder mixture before the filling operation. A disintegrating or solubilizing agent such as agar-agar, calcium carbonate or sodium carbonate can also be added to improve the availability of the medicament when the capsule is ingested.

Moreover, when desired or necessary, suitable binders, glidants, lubricants, sweetening agents, flavours, disintegrating agents and colouring agents can also be incorporated into the mixture. Suitable binders include starch, gelatin, natural sugars such as glucose or beta-lactose, corn sweeteners, natural and synthetic gums such as acacia, tragacanth or sodium alginate, carboxymethylcellulose, polyethylene glycol, waxes and the like. Lubricants used in these dosage forms include sodium oleate, sodium stearate, magnesium stearate, sodium benzoate, sodium acetate, sodium chloride and the like. Disintegrators include, without limitation, starch, methyl cellulose, agar, bentonite, xanthan gum and the like. Tablets are formulated, for example, by preparing a powder mixture, granulating or slugging, adding a lubricant and disintegrant and pressing into tablets. A powder mixture is prepared by mixing the compound, suitably comminuted, with a diluent or base as described above, and optionally, with a binder such as carboxymethylcellulose, an aliginate, gelatin, or polyvinyl pyrrolidone, a solution retardant such as paraffin, a resorption accelerator such as a quaternary salt and/or an absorption agent such as bentonite, kaolin or dicalcium phosphate. The powder mixture can be granulated by wetting with a binder such as syrup, starch paste, acadia mucilage or solutions of cellulosic or polymeric materials and forcing through a screen. As an alternative to granulating, the powder mixture can be run through the tablet machine and the result is imperfectly formed slugs broken into granules. The granules can be lubricated to prevent sticking to the tablet forming dies by means of the addition of stearic acid, a stearate salt, talc or mineral oil. The lubricated mixture is then compressed into tablets. The compounds of the present invention can also be combined with a free flowing inert carrier and compressed into tablets directly without going through the granulating or slugging steps. A clear or opaque protective coating consisting of a sealing coat of shellac, a coating of sugar or polymeric material and a polish coating of wax can be provided. Dyestuffs can be added to these coatings to distinguish different unit dosages.

Oral fluids such as solution, syrups and elixirs can be prepared in dosage unit form so that a given quantity contains a predetermined amount of the compound. Syrups can be prepared by dissolving the compound in a suitably flavoured aqueous solution, while elixirs are prepared through the use of a non-toxic alcoholic vehicle. Suspensions can be formulated by dispersing the compound in a non-toxic vehicle. Solubilizers and emulsifiers such as ethoxylated isostearyl alcohols and polyoxy ethylene sorbitol ethers, preservatives, flavor additive such as peppermint oil or natural sweeteners or saccharin or other artificial sweeteners, and the like can also be added.

Where appropriate, dosage unit compositions for oral administration can be microencapsulated. The composition can also be prepared to prolong or sustain the release as for example by coating or embedding particulate material in polymers, wax or the like.

The compounds of the invention may also be administered in the form of liposome delivery systems, such as small unilamellar vesicles, large unilamellar vesicles and multilamellar vesicles. Liposomes can be formed from a variety of phospholipids, such as cholesterol, stearylamine or phosphatidylcholines.

Pharmaceutical compositions adapted for transdermal administration may be presented as discrete patches intended to remain in intimate contact with the epidermis of the recipient for a prolonged period of time.

Pharmaceutical compositions adapted for topical administration may be formulated as ointments, creams, suspensions, lotions, powders, solutions, pastes, gels, sprays, aerosols or oils.

For treatments of the eye or other external tissues, for example mouth and skin, the compositions are preferably applied as a topical ointment or cream. When formulated in an ointment, the active ingredient may be employed with either a paraffinic or a water-miscible ointment base. Alternatively, the active ingredient may be formulated in a cream with an oil-in-water cream base or a water-in-oil base.

Pharmaceutical compositions adapted for topical administrations to the eye include eye drops wherein the active ingredient is dissolved or suspended in a suitable carrier, especially an aqueous solvent.

Pharmaceutical compositions adapted for topical administration in the mouth include lozenges, pastilles and mouth washes.

Pharmaceutical compositions adapted for rectal administration may be presented as suppositories or as enemas.

Dosage forms for nasal or inhaled administration may conveniently be formulated as aerosols, solutions, suspensions drops, gels or dry powders.

Pharmaceutical compositions adapted for vaginal administration may be presented as pessaries, tampons, creams, gels, pastes, foams or spray formulations.

Pharmaceutical compositions adapted for parental administration include aqueous and non-aqueous sterile injection solutions which may contain anti-oxidants, buffers, bacteriostats and solutes which render the composition isotonic with the blood of the intended recipient; and aqueous and non-aqueous sterile suspensions which may include suspending agents and thickening agents. The compositions may be presented in unit-dose or multi-dose containers, for example sealed ampoules and vials, and may be stored in a freeze-dried (lyophilized) condition requiring only the addition of the sterile liquid carrier, for example water for injections, immediately prior to use. Extemporaneous injection solutions and suspensions may be prepared from sterile powders, granules and tablets.

It should be understood that in addition to the ingredients particularly mentioned above, the compositions may include other agents conventional in the art having regard to the type of formulation in question, for example those suitable for oral administration may include flavouring agents.

A therapeutically effective amount of the agent will depend upon a number of factors including, for example, the age and weight of the subject, the precise condition requiring treatment and its severity, the nature of the formulation, and the route of administration, and will ultimately be at the discretion of the attendant physician or veterinarian. In particular, the subject to be treated is a mammal, particularly a human.

The agent may be administered in a daily dose. This amount may be given in a single dose per day or in a number (such as two, three, four, five or six) of sub-doses per day such that the total daily dose is the same.

Suitably, the amount of the compound of the invention administered according to the present invention will be an amount selected from 0.01 mg to 1 g per day (calculated as the free or unsalted compound).

We have found that the compounds defined in the present invention, or a pharmaceutically acceptable salt thereof, or pharmaceutical compositions containing them, are capable of degrading the estrogen-receptor.

Accordingly, the compounds of the present invention are expected to be potentially useful agents in the treatment of diseases or medical conditions mediated alone or in part by the estrogen receptor.

Provided herein are methods of treatment or prevention of diseases, disorders and conditions mediated by the estrogen receptor. A method may comprise administering to a subject, e.g. a subject in need thereof, a therapeutically effective amount of a compound of the invention.

Thus in one aspect there is provided a compound of the invention for use in therapy

Thus in one aspect there is provided a compound of the invention for use in treating diseases, disorders or conditions mediated by the estrogen receptor

Thus in one aspect there is provided the use of a compound of the invention in the manufacture of a medicament for treating diseases, disorders or conditions mediated by the estrogen receptor.

In a further aspect there is provided a method of treatment of diseases, disorders or conditions mediated by the estrogen receptor in a mammal comprising administering a therapeutically effective amount of a compound of the invention.

The compound of the invention are useful in the treatment of estrogen receptor associated conditions. An “estrogen receptor-associated condition,” as used herein, denotes a condition or disorder which can be treated by modulating the function or activity of an estrogen receptor in a subject, wherein treatment comprises prevention, partial alleviation or cure of the condition or disorder. Modulation may occur locally, for example, within certain tissues of the subject, or more extensively throughout a subject being treated for such a condition or disorder.

In one aspect the estrogen mediated disease or condition is breast cancer

The compounds of the present invention may be used in combination with or include one or more other therapeutic agents and may be administered either sequentially or simultaneously by any convenient route in separate or combined pharmaceutical compositions.

The therapeutically effective amount of the further therapeutic agents of the present invention will depend upon a number of factors including, for example, the age and weight of the mammal, the precise condition requiring treatment, the severity of the condition, the nature of the formulation, and the route of administration. Ultimately, the therapeutically effective amount will be at the discretion of the attendant physician or veterinarian. The relative timings of administration will be selected in order to achieve the desired combined therapeutic effect.

The compounds of the present invention and further therapeutic agent(s) may be employed in combination by administration simultaneously in a unitary pharmaceutical composition including both compounds. Alternatively, the combination may be administered separately in separate pharmaceutical compositions, each including one of the compounds in a sequential manner wherein, for example, the compound of the invention is administered first and the other second and vice versa. Such sequential administration may be close in time (e.g. simultaneously) or remote in time. Furthermore, it does not matter if the compounds are administered in the same dosage form, e.g. one compound may be administered topically and the other compound may be administered orally. Suitably, both compounds are administered orally.

The combinations may be presented as a combination kit. By the term “combination kit” “or kit of parts” as used herein is meant the pharmaceutical composition or compositions that are used to administer the combination according to the invention. When both compounds are administered simultaneously, the combination kit can contain both compounds in a single pharmaceutical composition, such as a tablet, or in separate pharmaceutical compositions. When the compounds are not administered simultaneously, the combination kit will contain each compound in separate pharmaceutical compositions either in a single package or in separate pharmaceutical compositions in separate packages.

The combination kit can also be provided by instruction, such as dosage and administration instructions. Such dosage and administration instructions can be of the kind that are provided to a doctor, for example by a drug product label, or they can be of the kind that are provided by a doctor, such as instructions to a patient.

When the combination is administered separately in a sequential manner wherein one is administered first and the other second or vice versa, such sequential administration may be close in time or remote in time. For example, administration of the other agent several minutes to several dozen minutes after the administration of the first agent, and administration of the other agent several hours to several days after the administration of the first agent are included, wherein the lapse of time is not limited, For example, one agent may be administered once a day, and the other agent may be administered 2 or 3 times a day, or one agent may be administered once a week, and the other agent may be administered once a day and the like.

It will be clear to a person skilled in the art that, where appropriate, the other therapeutic ingredients(s) may be used in the form of salts, for example as alkali metal or amine salts or as acid addition salts, or prodrugs, or as esters, for example lower alkyl esters, or as solvates, for example hydrates, to optimise the activity and/or stability and/or physical characteristics, such as solubility, of the therapeutic ingredient. It will be clear also that, where appropriate, the therapeutic ingredients may be used in optically pure form.

When combined in the same composition it will be appreciated that the two compounds must be stable and compatible with each other and the other components of the composition and may be formulated for administration. When formulated separately they may be provided in any convenient composition, conveniently, in such a manner as known for such compounds in the art.

When the compound of formula (I) is used in combination with a second therapeutic agent active against the same disease, condition or disorder, the dose of each compound may differ from that when the compound is used alone. Appropriate doses will be readily appreciated by those skilled in the art.

In the embodiment, the compound of compound of formula (I) or a pharmaceutically acceptable salt thereof may be employed with other therapeutic methods of cancer treatment. In particular, in anti-neoplastic therapy, combination therapy with other chemotherapeutic, hormonal, antibody agents as well as surgical and/or radiation treatments other than those mentioned above are envisaged.

As indicated, therapeutically effective amounts of the compound of compound of formula (I) or a pharmaceutically acceptable salt thereof are discussed above. The therapeutically effective amount of the further therapeutic agents of the present invention will depend upon a number of factors including, for example, the age and weight of the mammal, the precise condition requiring treatment, the severity of the condition, the nature of the formulation, and the route of administration. Ultimately, the therapeutically effective amount will be at the discretion of the attendant physician or veterinarian. The relative timings of administration will be selected in order to achieve the desired combined therapeutic effect.

In one embodiment, the further anti-cancer therapy is surgical and/or radiotherapy.

In one embodiment, the further anti-cancer therapy is at least one additional anti-neoplastic agent.

Any anti-neoplastic agent that has activity versus a susceptible tumor being treated may be utilized in the combination. Typical anti-neoplastic agents useful include, but are not limited to, anti-microtubule agents such as diterpenoids and vinca alkaloids; platinum coordination complexes; alkylating agents such as nitrogen mustards, oxazaphosphorines, alkylsulfonates, nitrosoureas, and triazenes; antibiotic agents such as anthracyclins, actinomycins and bleomycins; topoisomerase II inhibitors such as epipodophyllotoxins; antimetabolites such as purine and pyrimidine analogues and anti-folate compounds; topoisomerase I inhibitors such as camptothecins; hormones and hormonal analogues; signal transduction pathway inhibitors; non-receptor tyrosine angiogenesis inhibitors; immunotherapeutic agents; proapoptotic agents; and cell cycle signaling inhibitors.

Anti-Microtubule or Anti-Mitotic Agents:

Anti-microtubule or anti-mitotic agents are phase specific agents active against the microtubules of tumor cells during M or the mitosis phase of the cell cycle. Examples of anti-microtubule agents include, but are not limited to, diterpenoids and vinca alkaloids.

Diterpenoids, which are derived from natural sources, are phase specific anti-cancer agents that operate at the G₂/M phases of the cell cycle. It is believed that the diterpenoids stabilize the β-tubulin subunit of the microtubules, by binding with this protein. Disassembly of the protein appears then to be inhibited with mitosis being arrested and cell death following. Examples of diterpenoids include, but are not limited to, paclitaxel and its analog docetaxel.

Paclitaxel, 5β,20-epoxy-1,2α,4,7β,10β,13α-hexa-hydroxytax-11-en-9-one 4,10-diacetate 2-benzoate 13-ester with (2R,3S)—N-benzoyl-3-phenylisoserine; is a natural diterpene product isolated from the Pacific yew tree Taxus brevifolia and is commercially available as an injectable solution TAXOL®. It is a member of the taxane family of terpenes. Paclitaxel has been approved for clinical use in the treatment of refractory ovarian cancer in the United States (Markman et al., Yale Journal of Biology and Medicine, 64:583, 1991; McGuire et al., Ann. Intem, Med., 111:273, 1989) and for the treatment of breast cancer (Holmes et al., J. Nat. Cancer Inst., 83:1797, 1991.) It is a potential candidate for treatment of neoplasms in the skin (Einzig et. al., Proc. Am. Soc. Clin. Oncol., 20:46) and head and neck carcinomas (Forastire et. al., Sem. Oncol., 20:56, 1990). The compound also shows potential for the treatment of polycystic kidney disease (Woo et. al., Nature, 368:750. 1994), lung cancer and malaria. Treatment of patients with paclitaxel results in bone marrow suppression (multiple cell lineages, Ignoff, R. J. et. al, Cancer Chemotherapy Pocket Guide, 1998) related to the duration of dosing above a threshold concentration (50 nM) (Kearns, C. M. et. al., Seminars in Oncology, 3(6) p. 16-23, 1995).

Docetaxel, (2R,3S)—N-carboxy-3-phenylisoserine,N-tert-butyl ester, 13-ester with 5β-20-epoxy-1,2α,4,7β,10β,13α-hexahydroxytax-11-en-9-one 4-acetate 2-benzoate, trihydrate; is commercially available as an injectable solution as TAXOTERE®. Docetaxel is indicated for the treatment of breast cancer. Docetaxel is a semisynthetic derivative of paclitaxel q.v., prepared using a natural precursor, 10-deacetyl-baccatin III, extracted from the needle of the European Yew tree.

Vinca alkaloids are phase specific anti-neoplastic agents derived from the periwinkle plant. Vinca alkaloids act at the M phase (mitosis) of the cell cycle by binding specifically to tubulin. Consequently, the bound tubulin molecule is unable to polymerize into microtubules. Mitosis is believed to be arrested in metaphase with cell death following. Examples of vinca alkaloids include, but are not limited to, vinblastine, vincristine, and vinorelbine.

Vinblastine, vincaleukoblastine sulfate, is commercially available as VELBAN® as an injectable solution. Although, it has possible indication as a second line therapy of various solid tumors, it is primarily indicated in the treatment of testicular cancer and various lymphomas including Hodgkin's Disease; and lymphocytic and histiocytic lymphomas. Myelosuppression is the dose limiting side effect of vinblastine.

Vincristine, vincaleukoblastine, 22-oxo-, sulfate, is commercially available as ONCOVIN® as an injectable solution. Vincristine is indicated for the treatment of acute leukemias and has also found use in treatment regimens for Hodgkin's and non-Hodgkin's malignant lymphomas. Alopecia and neurologic effects are the most common side effect of vincristine and to a lesser extent myelosupression and gastrointestinal mucositis effects occur.

Vinorelbine, 3′,4′-didehydro-4′-deoxy-C′-norvincaleukoblastine [R—(R*,R*)-2,3-dihydroxybutanedioate (1:2)(salt)], commercially available as an injectable solution of vinorelbine tartrate (NAVELBINE®), is a semisynthetic vinca alkaloid. Vinorelbine is indicated as a single agent or in combination with other chemotherapeutic agents, such as cisplatin, in the treatment of various solid tumors, particularly non-small cell lung, advanced breast, and hormone refractory prostate cancers. Myelosuppression is the most common dose limiting side effect of vinorelbine.

Platinum Coordination Complexes:

Platinum coordination complexes are non-phase specific anti-cancer agents, which are interactive with DNA. The platinum complexes enter tumor cells, undergo, aquation and form intra- and interstrand crosslinks with DNA causing adverse biological effects to the tumor. Examples of platinum coordination complexes include, but are not limited to, oxaliplatin, cisplatin and carboplatin.

Cisplatin, cis-diamminedichloroplatinum, is commercially available as PLATINOL® as an injectable solution. Cisplatin is primarily indicated in the treatment of metastatic testicular and ovarian cancer and advanced bladder cancer.

Carboplatin, platinum, diammine [1,1-cyclobutane-dicarboxylate(2-)-O,O′], is commercially available as PARAPLATIN® as an injectable solution. Carboplatin is primarily indicated in the first and second line treatment of advanced ovarian carcinoma.

Alkylating Agents:

Alkylating agents are non-phase anti-cancer specific agents and strong electrophiles. Typically, alkylating agents form covalent linkages, by alkylation, to DNA through nucleophilic moieties of the DNA molecule such as phosphate, amino, sulfhydryl, hydroxyl, carboxyl, and imidazole groups. Such alkylation disrupts nucleic acid function leading to cell death. Examples of alkylating agents include, but are not limited to, nitrogen mustards such as cyclophosphamide, melphalan, and chlorambucil; alkyl sulfonates such as busulfan; nitrosoureas such as carmustine; and triazenes such as dacarbazine.

Cyclophosphamide, 2-[bis(2-chloroethyl)amino]tetrahydro-2H-1,3,2-oxazaphosphorine 2-oxide monohydrate, is commercially available as an injectable solution or tablets as CYTOXAN®. Cyclophosphamide is indicated as a single agent or in combination with other chemotherapeutic agents, in the treatment of malignant lymphomas, multiple myeloma, and leukemias.

Melphalan, 4-[bis(2-chloroethyl)amino]-L-phenylalanine, is commercially available as an injectable solution or tablets as ALKERAN®. Melphalan is indicated for the palliative treatment of multiple myeloma and non-respectable epithelial carcinoma of the ovary. Bone marrow suppression is the most common dose limiting side effect of melphalan.

Chlorambucil, 4-[bis(2-chloroethyl)amino]benzenebutanoic acid, is commercially available as LEUKERAN® tablets. Chlorambucil is indicated for the palliative treatment of chronic lymphatic leukemia, and malignant lymphomas such as lymphosarcoma, giant follicular lymphoma, and Hodgkin's disease.

Busulfan, 1,4-butanediol dimethanesulfonate, is commercially available as MYLERAN® TABLETS. Busulfan is indicated for the palliative treatment of chronic myelogenous leukemia.

Carmustine, 1,3-[bis(2-chloroethyl)-1-nitrosourea, is commercially available as single vials of lyophilized material as BiCNU®. Carmustine is indicated for the palliative treatment as a single agent or in combination with other agents for brain tumors, multiple myeloma, Hodgkin's disease, and non-Hodgkin's lymphomas.

Dacarbazine, 5-(3,3-dimethyl-1-triazeno)-imidazole-4-carboxamide, is commercially available as single vials of material as DTIC-Dome®. Dacarbazine is indicated for the treatment of metastatic malignant melanoma and in combination with other agents for the second line treatment of Hodgkin's Disease.

Antibiotic Anti-Neoplastics:

Antibiotic anti-neoplastics are non-phase specific agents, which bind or intercalate with DNA. Typically, such action results in stable DNA complexes or strand breakage, which disrupts ordinary function of the nucleic acids leading to cell death. Examples of antibiotic anti-neoplastic agents include, but are not limited to, actinomycins such as dactinomycin, anthrocyclins such as daunorubicin and doxorubicin; and bleomycins.

Dactinomycin, also known as Actinomycin D, is commercially available in injectable form as COSMEGEN®. Dactinomycin is indicated for the treatment of Wilm's tumor and rhabdomyosarcoma.

Daunorubicin, (8S-cis+8-acetyl-10-[(3-amino-2,3,6-trideoxy-α-L-lyxo-hexopyranosyl)oxy]-7,8,9,10-tetrahydro-6,8,11-trihydroxy-1-methoxy-5,12 naphthacenedione hydrochloride, is commercially available as a liposomal injectable form as DAUNOXOME® or as an injectable as CERUBIDINE®. Daunorubicin is indicated for remission induction in the treatment of acute nonlymphocytic leukemia and advanced HIV associated Kaposi's sarcoma.

Doxorubicin, (8S,10S)-10-[(3-amino-2,3,6-trideoxy-α-L-lyxo-hexopyranosyl)oxy]-8-glycoloyl, 7,8,9,10-tetrahydro-6,8,11-trihydroxy-1-methoxy-5,12 naphthacenedione hydrochloride, is commercially available as an injectable form as RUBEX® or ADRIAMYCIN RDF®. Doxorubicin is primarily indicated for the treatment of acute lymphoblastic leukemia and acute myeloblastic leukemia, but is also a useful component in the treatment of some solid tumors and lymphomas.

Bleomycin, a mixture of cytotoxic glycopeptide antibiotics isolated from a strain of Streptomyces verticillus, is commercially available as BLENOXANE®. Bleomycin is indicated as a palliative treatment, as a single agent or in combination with other agents, of squamous cell carcinoma, lymphomas, and testicular carcinomas.

Topoisomerase II Inhibitors:

Topoisomerase II inhibitors include, but are not limited to, epipodophyllotoxins.

Epipodophyllotoxins are phase specific anti-neoplastic agents derived from the mandrake plant. Epipodophyllotoxins typically affect cells in the S and G₂ phases of the cell cycle by forming a ternary complex with topoisomerase II and DNA causing DNA strand breaks. The strand breaks accumulate and cell death follows. Examples of epipodophyllotoxins include, but are not limited to, etoposide and teniposide.

Etoposide, 4′-demethyl-epipodophyllotoxin 9[4,6-0-(R)-ethylidene-β-D-glucopyranoside], is commercially available as an injectable solution or capsules as VePESID® and is commonly known as VP-16. Etoposide is indicated as a single agent or in combination with other chemotherapy agents in the treatment of testicular and non-small cell lung cancers.

Teniposide, 4′-demethyl-epipodophyllotoxin 9 [4,6-0-(R)-thenylidene-β-D-glucopyranoside], is commercially available as an injectable solution as VUMON® and is commonly known as VM-26. Teniposide is indicated as a single agent or in combination with other chemotherapy agents in the treatment of acute leukemia in children.

Antimetabolite Neoplastic Agents:

Antimetabolite neoplastic agents are phase specific anti-neoplastic agents that act at S phase (DNA synthesis) of the cell cycle by inhibiting DNA synthesis or by inhibiting purine or pyrimidine base synthesis and thereby limiting DNA synthesis. Consequently, S phase does not proceed and cell death follows. Examples of antimetabolite anti-neoplastic agents include, but are not limited to, fluorouracil, methotrexate, cytarabine, mecaptopurine, thioguanine, and gemcitabine.

5-fluorouracil, 5-fluoro-2,4-(1H,3H)pyrimidinedione, is commercially available as fluorouracil. Administration of 5-fluorouracil leads to inhibition of thymidylate synthesis and is also incorporated into both RNA and DNA. The result typically is cell death. 5-fluorouracil is indicated as a single agent or in combination with other chemotherapy agents in the treatment of carcinomas of the breast, colon, rectum, stomach and pancreas. Other fluoropyrimidine analogs include 5-fluoro deoxyuridine (floxuridine) and 5-fluorodeoxyuridine monophosphate.

Cytarabine, 4-amino-1-β-D-arabinofuranosyl-2 (1H)-pyrimidinone, is commercially available as CYTOSAR-U® and is commonly known as Ara-C. It is believed that cytarabine exhibits cell phase specificity at S-phase by inhibiting DNA chain elongation by terminal incorporation of cytarabine into the growing DNA chain. Cytarabine is indicated as a single agent or in combination with other chemotherapy agents in the treatment of acute leukemia. Other cytidine analogs include 5-azacytidine and 2′,2′-difluorodeoxycytidine (gemcitabine).

Mercaptopurine, 1,7-dihydro-6H-purine-6-thione monohydrate, is commercially available as PURINETHOL®. Mercaptopurine exhibits cell phase specificity at S-phase by inhibiting DNA synthesis by an as of yet unspecified mechanism. Mercaptopurine is indicated as a single agent or in combination with other chemotherapy agents in the treatment of acute leukemia. A useful mercaptopurine analog is azathioprine.

Thioguanine, 2-amino-1,7-dihydro-6H-purine-6-thione, is commercially available as TABLOID®. Thioguanine exhibits cell phase specificity at S-phase by inhibiting DNA synthesis by an as of yet unspecified mechanism. Thioguanine is indicated as a single agent or in combination with other chemotherapy agents in the treatment of acute leukemia. Other purine analogs include pentostatin, erythrohydroxynonyladenine, fludarabine phosphate, and cladribine.

Gemcitabine, 2′-deoxy-2′,2′-difluorocytidine monohydrochloride (β-isomer), is commercially available as GEMZAR®. Gemcitabine exhibits cell phase specificity at S-phase and by blocking progression of cells through the G1/S boundary. Gemcitabine is indicated in combination with cisplatin in the treatment of locally advanced non-small cell lung cancer and alone in the treatment of locally advanced pancreatic cancer.

Methotrexate, N-[4[[(2,4-diamino-6-pteridinyl)methyl]methylamino]benzoyl]-L-glutamic acid, is commercially available as methotrexate sodium. Methotrexate exhibits cell phase effects specifically at S-phase by inhibiting DNA synthesis, repair and/or replication through the inhibition of dyhydrofolic acid reductase which is required for synthesis of purine nucleotides and thymidylate. Methotrexate is indicated as a single agent or in combination with other chemotherapy agents in the treatment of choriocarcinoma, meningeal leukemia, non-Hodgkin's lymphoma, and carcinomas of the breast, head, neck, ovary and bladder.

Topoisomerase I Inhibitors:

Camptothecins, including, camptothecin and camptothecin derivatives are available or under development as Topoisomerase I inhibitors. Camptothecins cytotoxic activity is believed to be related to its Topoisomerase I inhibitory activity. Examples of camptothecins include, but are not limited to irinotecan, topotecan, and the various optical forms of 7-(4-methylpiperazino-methylene)-10,11-ethylenedioxy-20-camptothecin described below.

Irinotecan HCl, (4S)-4,11-diethyl-4-hydroxy-9-[(4-piperidinopiperidino) carbonyloxy]-1H-pyrano[3′,4′,6,7]indolizino[1,2-b]quinoline-3,14(4H,12H)-dione hydrochloride, is commercially available as the injectable solution CAMPTOSAR®. Irinotecan is a derivative of camptothecin which binds, along with its active metabolite SN-38, to the topoisomerase I-DNA complex. It is believed that cytotoxicity occurs as a result of irreparable double strand breaks caused by interaction of the topoisomerase I:DNA:irintecan or SN-38 ternary complex with replication enzymes. Irinotecan is indicated for treatment of metastatic cancer of the colon or rectum.

Topotecan HCl, (S)-10-[(dimethylamino)methyl]-4-ethyl-4,9-dihydroxy-1H-pyrano[3′,4′,6,7]indolizino[1,2-b]quinoline-3,14-(4H,12H)-dione monohydrochloride, is commercially available as the injectable solution HYCAMTIN®. Topotecan is a derivative of camptothecin which binds to the topoisomerase I-DNA complex and prevents religation of singles strand breaks caused by Topoisomerase I in response to torsional strain of the DNA molecule. Topotecan is indicated for second line treatment of metastatic carcinoma of the ovary and small cell lung cancer.

Hormones and Hormonal Analogues:

Hormones and hormonal analogues are useful compounds for treating cancers in which there is a relationship between the hormone(s) and growth and/or lack of growth of the cancer. Examples of hormones and hormonal analogues useful in cancer treatment include, but are not limited to, adrenocorticosteroids such as prednisone and prednisolone which are useful in the treatment of malignant lymphoma and acute leukemia in children; aminoglutethimide and other aromatase inhibitors such as anastrozole, letrazole, vorazole, and exemestane useful in the treatment of adrenocortical carcinoma and hormone dependent breast carcinoma containing estrogen receptors; progestrins such as megestrol acetate useful in the treatment of hormone dependent breast cancer and endometrial carcinoma; estrogens, estrogens, and anti-estrogens such as fulvestrant, flutamide, nilutamide, bicalutamide, cyproterone acetate and 5α-reductases such as finasteride and dutasteride, useful in the treatment of prostatic carcinoma and benign prostatic hypertrophy; anti-estrogens such as tamoxifen, toremifene, raloxifene, droloxifene, iodoxyfene, as well as selective estrogen receptor modulators (SERMS) such those described in U.S. Pat. Nos. 5,681,835, 5,877,219, and 6,207,716, useful in the treatment of hormone dependent breast carcinoma and other susceptible cancers; and gonadotropin-releasing hormone (GnRH) and analogues thereof which stimulate the release of leutinizing hormone (LH) and/or follicle stimulating hormone (FSH) for the treatment prostatic carcinoma, for instance, LHRH agonists and antagonists such as goserelin acetate and luprolide.

Signal Transduction Pathway Inhibitors:

Signal transduction pathway inhibitors are those inhibitors, which block or inhibit a chemical process which evokes an intracellular change. As used herein this change is cell proliferation or differentiation. Signal transduction inhibitors useful in the present invention include inhibitors of receptor tyrosine kinases, non-receptor tyrosine kinases, SH2/SH3domain blockers, serine/threonine kinases, phosphotidyl inositol-3 kinases, myo-inositol signaling, and Ras oncogenes.

Several protein tyrosine kinases catalyse the phosphorylation of specific tyrosyl residues in various proteins involved in the regulation of cell growth. Such protein tyrosine kinases can be broadly classified as receptor or non-receptor kinases.

Receptor tyrosine kinases are transmembrane proteins having an extracellular ligand binding domain, a transmembrane domain, and a tyrosine kinase domain. Receptor tyrosine kinases are involved in the regulation of cell growth and are generally termed growth factor receptors. Inappropriate or uncontrolled activation of many of these kinases, i.e. aberrant kinase growth factor receptor activity, for example by over-expression or mutation, has been shown to result in uncontrolled cell growth. Accordingly, the aberrant activity of such kinases has been linked to malignant tissue growth. Consequently, inhibitors of such kinases could provide cancer treatment methods. Growth factor receptors include, for example, epidermal growth factor receptor (EGFr), platelet derived growth factor receptor (PDGFr), erbB2, erbB4, ret, vascular endothelial growth factor receptor (VEGFr), tyrosine kinase with immunoglobulin-like and epidermal growth factor homology domains (TIE-2), insulin growth factor-I (IGFI) receptor, macrophage colony stimulating factor (cfms), BTK, ckit, cmet, fibroblast growth factor (FGF) receptors, Trk receptors (TrkA, TrkB, and TrkC), ephrin (eph) receptors, and the RET protooncogene. Several inhibitors of growth receptors are under development and include ligand antagonists, antibodies, tyrosine kinase inhibitors and anti-sense oligonucleotides. Growth factor receptors and agents that inhibit growth factor receptor function are described, for instance, in Kath, John C., Exp. Opin. Ther. Patents (2000) 10(6):803-818; Shawver et al DDT Vol 2, No. 2 Feb. 1997; and Lofts, F. J. et al, “Growth factor receptors as targets”, New Molecular Targets for Cancer Chemotherapy, ed. Workman, Paul and Kerr, David, CRC press 1994, London.

Tyrosine kinases, which are not growth factor receptor kinases are termed non-receptor tyrosine kinases. Non-receptor tyrosine kinases useful in the present invention, which are targets or potential targets of anti-cancer drugs, include cSrc, Lck, Fyn, Yes, Jak, cAbl, FAK (Focal adhesion kinase), Brutons tyrosine kinase, and Bcr-Abl. Such non-receptor kinases and agents which inhibit non-receptor tyrosine kinase function are described in Sinh, S. and Corey, S. J., (1999) Journal of Hematotherapy and Stem Cell Research 8 (5): 465-80; and Bolen, J. B., Brugge, J. S., (1997) Annual review of Immunology. 15: 371-404. SH2/SH3 domain blockers are agents that disrupt SH2 or SH3 domain binding in a variety of enzymes or adaptor proteins including, PI3-K p85 subunit, Src family kinases, adaptor molecules (Shc, Crk, Nck, Grb2) and Ras-GAP. SH2/SH3 domains as targets for anti-cancer drugs are discussed in Smithgall, T. E. (1995), Journal of Pharmacological and Toxicological Methods. 34(3) 125-32.

Inhibitors of Serine/Threonine Kinases including MAP kinase cascade blockers which include blockers of Raf kinases (rafk), Mitogen or Extracellular Regulated Kinase (MEKs), and Extracellular Regulated Kinases (ERKs); and Protein kinase C family member blockers including blockers of PKCs (alpha, beta, gamma, epsilon, mu, lambda, iota, zeta). IkB kinase family (IKKa, IKKb), PKB family kinases, akt kinase family members, and TGF beta receptor kinases. Such Serine/Threonine kinases and inhibitors thereof are described in Yamamoto, T., Taya, S., Kaibuchi, K., (1999), Journal of Biochemistry. 126 (5) 799-803; Brodt, P, Samani, A., and Navab, R. (2000), Biochemical Pharmacology, 60. 1101-1107; Massague, J., Weis-Garcia, F. (1996) Cancer Surveys. 27:41-64; Philip, P. A., and Harris, A. L. (1995), Cancer Treatment and Research. 78: 3-27, Lackey, K. et al Bioorganic and Medicinal Chemistry Letters, (10), 2000, 223-226; U.S. Pat. No. 6,268,391; and Martinez-Iacaci, L., et al, Int. J. Cancer (2000), 88(1), 44-52.

Inhibitors of Phosphotidyl inositol-3 Kinase family members including blockers of PI3-kinase, ATM, DNA-PK, and Ku are also useful in the present invention. Such kinases are discussed in Abraham, R. T. (1996), Current Opinion in Immunology. 8 (3) 412-8; Canman, C. E., Lim, D. S. (1998), Oncogene 17 (25) 3301-3308; Jackson, S. P. (1997), International Journal of Biochemistry and Cell Biology. 29 (7):935-8; and Zhong, H. et al, Cancer res, (2000) 60(6), 1541-1545.

Also useful in the present invention are Myo-inositol signaling inhibitors such as phospholipase C blockers and Myoinositol analogues. Such signal inhibitors are described in Powis, G., and Kozikowski A., (1994) New Molecular Targets for Cancer Chemotherapy ed., Paul Workman and David Kerr, CRC press 1994, London.

Another group of signal transduction pathway inhibitors are inhibitors of Ras Oncogene. Such inhibitors include inhibitors of farnesyltransferase, geranyl-geranyl transferase, and CAAX proteases as well as anti-sense oligonucleotides, ribozymes and immunotherapy. Such inhibitors have been shown to block ras activation in cells containing wild type mutant ras, thereby acting as antiproliferation agents. Ras oncogene inhibition is discussed in Scharovsky, O. G., Rozados, V. R., Gervasoni, S. I. Matar, P. (2000), Journal of Biomedical Science. 7(4) 292-8; Ashby, M. N. (1998), Current Opinion in Lipidology. 9 (2) 99-102; and BioChim. Biophys. Acta, (19899) 1423(3):19-30.

As mentioned above, antibody antagonists to receptor kinase ligand binding may also serve as signal transduction inhibitors. This group of signal transduction pathway inhibitors includes the use of humanized antibodies to the extracellular ligand binding domain of receptor tyrosine kinases. For example Imclone C225 EGFR specific antibody (see Green, M. C. et al, Monoclonal Antibody Therapy for Solid Tumors, Cancer Treat. Rev., (2000), 26(4), 269-286); Herceptin® erbB2 antibody (see Tyrosine Kinase Signalling in Breast cancer:erbB Family Receptor Tyrosine Kinases, Breast cancer Res., 2000, 2(3), 176-183); and 2CB VEGFR2 specific antibody (see Brekken, R. A. et al, Selective Inhibition of VEGFR2 Activity by a monoclonal Anti-VEGF antibody blocks tumor growth in mice, Cancer Res. (2000) 60, 5117-5124).

Anti-Angiogenic Agents:

(i) Anti-angiogenic agents including non-receptor MEK angiogenesis inhibitors may also be useful. Anti-angiogenic agents such as those which inhibit the effects of vascular endothelial growth factor, (for example the anti-vascular endothelial cell growth factor antibody bevacizumab [Avastin™], and compounds that work by other mechanisms (for example linomide, inhibitors of integrin αvβ3 function, endostatin and angiostatin);

Immunotherapeutic Agents:

Agents used in immunotherapeutic regimens may also be useful in combination with the compounds of formula (I). Immunotherapy approaches, including for example ex-vivo and in-vivo approaches to increase the immunogenicity of patient tumour cells, such as transfection with cytokines such as interleukin 2, interleukin 4 or granulocyte-macrophage colony stimulating factor, approaches to decrease T-cell anergy, approaches using transfected immune cells such as cytokine-transfected dendritic cells, approaches using cytokine-transfected tumour cell lines and approaches using anti-idiotypic antibodies

Proapoptotic Agents:

Agents used in proapoptotic regimens (e.g., bcl-2 antisense oligonucleotides) may also be used in the combination of the present invention.

Cell Cycle Signalling Inhibitors

Cell cycle signalling inhibitors inhibit molecules involved in the control of the cell cycle. A family of protein kinases called cyclin dependent kinases (CDKs) and their interaction with a family of proteins termed cyclins controls progression through the eukaryotic cell cycle. The coordinate activation and inactivation of different cyclin/CDK complexes is necessary for normal progression through the cell cycle. Several inhibitors of cell cycle signalling are under development. For instance, examples of cyclin dependent kinases, including CDK2, CDK4, and CDK6 and inhibitors for the same are described in, for instance, Rosania et al, Exp. Opin. Ther. Patents (2000) 10(2):215-230.

In one embodiment, the combination of the present invention comprises a compound of formula I or a salt or solvate thereof and at least one anti-neoplastic agent selected from anti-microtubule agents, platinum coordination complexes, alkylating agents, antibiotic agents, topoisomerase II inhibitors, antimetabolites, topoisomerase I inhibitors, hormones and hormonal analogues, signal transduction pathway inhibitors, non-receptor tyrosine MEK angiogenesis inhibitors, immunotherapeutic agents, proapoptotic agents, and cell cycle signaling inhibitors.

In one embodiment, the combination of the present invention comprises a compound of formula I or a salt or solvate thereof and at least one anti-neoplastic agent which is an anti-microtubule agent selected from diterpenoids and vinca alkaloids.

In a further embodiment, at least one anti-neoplastic agent is a diterpenoid.

In a further embodiment, at least one anti-neoplastic agent is a vinca alkaloid.

In one embodiment, the combination of the present invention comprises a compound of formula I or a salt or solvate thereof and at least one anti-neoplastic agent, which is a platinum coordination complex.

In a further embodiment, at least one anti-neoplastic agent is paclitaxel, carboplatin, or vinorelbine.

In a further embodiment, at least one anti-neoplastic agent is carboplatin.

In a further embodiment, at least one anti-neoplastic agent is vinorelbine.

In a further embodiment, at least one anti-neoplastic agent is paclitaxel.

In one embodiment, the combination of the present invention comprises a compound of formula I and salts or solvates thereof and at least one anti-neoplastic agent which is a signal transduction pathway inhibitor.

In a further embodiment the signal transduction pathway inhibitor is an inhibitor of a growth factor receptor kinase VEGFR2, TIE2, PDGFR, BTK, erbB2, EGFr, IGFR-1, TrkA, TrkB, TrkC, or c-fms.

In a further embodiment the signal transduction pathway inhibitor is an inhibitor of a serine/threonine kinase rafk, akt, or PKC-zeta.

In a further embodiment the signal transduction pathway inhibitor is an inhibitor of a non-receptor tyrosine kinase selected from the src family of kinases.

In a further embodiment the signal transduction pathway inhibitor is an inhibitor of c-src.

In a further embodiment the signal transduction pathway inhibitor is an inhibitor of Ras oncogene selected from inhibitors of farnesyl transferase and geranylgeranyl transferase.

In a further embodiment the signal transduction pathway inhibitor is an inhibitor of a serine/threonine kinase selected from the group consisting of PI3K.

In a further embodiment the signal transduction pathway inhibitor is a dual EGFr/erbB2 inhibitor, for example N-{3-Chloro-4-[(3-fluorobenzyl)oxy]phenyl}-6-[5-({[2-(methanesulphonyl)ethyl]amino}methyl)-2-furyl]-4-quinazolinamine (structure below):

In one embodiment, the combination of the present invention comprises a compound of formula I or a salt or solvate thereof and at least one anti-neoplastic agent which is a cell cycle signaling inhibitor.

In further embodiment, cell cycle signaling inhibitor is an inhibitor of CDK2, CDK4 or CDK6.

Particular components of combination therapy include combinations with other anti-estrogens including tamoxifen and/or fulvestrant.

In one embodiment the mammal in the methods and uses of the present invention is a human.

General Synthetic Methods

Compounds of general formula (I) may be prepared by methods known in the art of organic synthesis as set forth in the specific Examples described below. In all of the methods, it is well understood that protecting groups for sensitive or reactive groups may be employed where necessary in accordance with general principles of chemistry. Protecting groups are manipulated according to standard methods of organic synthesis (T. W. Green and P. G. M. Wuts (1999) Protective Groups in Organic Synthesis, 3^(rd) edition, John Wiley & Sons). These groups are removed at a convenient stage of the compound synthesis using methods that are readily apparent to those skilled in the art. The selection of processes as well as the reaction conditions and order of their execution shall be consistent with the preparation of compounds of Formula (I).

EXPERIMENTAL Abbreviations

DCM: dichloromethane.

DIPEA: N,N-diisopropylethylamine. DMF: N,N-dimethylformamide.

h: hour. HATU: 2-(7-aza-1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate. HPLC: high-performance liquid chromatography. LCMS: liquid chromatography-mass spectrometry Min: minutes. NMR: Nuclear magnetic resonance. RT: retention time. tBu: tert-butoxide. TFA: trifluoroacetic acid. THF: tetrahydrofuran. TMSCl: trimethylsilyl chloride.

LCMS Method:

The analysis was conducted on an Acquity UPLC BEH C18 column (50 mm×2.1 mm internal diameter 1.7 μm packing diameter) at 40° C.

The solvents employed were:

A=0.1% v/v solution of formic acid in water.

B=0.1% v/v solution of formic acid in acetonitrile.

The gradient employed was as follows:

Time Flow Rate (minutes) (mL/min) % A % B 0 1 97 3 1.5 1 0 100 1.9 1 0 100 2.0 1 97 3

The UV detection was an averaged signal from wavelength of 210 nm to 350 nm and mass spectra were recorded on a mass spectrometer using alternate-scan positive and negative mode electrospray ionization.

The following illustrates the mobile phases and gradients used when compounds underwent purification by mass-directed autopreparative HPLC.

Mass-Directed Autopreparative HPLC (Formic Acid Modifier)

The HPLC analysis was conducted on a Sunfire C18 column (150 mm×30 mm internal diameter, 5 μm packing diameter) at ambient temperature.

The solvents employed were:

A=0.1% v/v solution of formic acid in water.

B=0.1% v/v solution of formic acid in acetonitrile.

Mass-Directed Autopreparative HPLC (Ammonium Bicarbonate Modifier)

The HPLC analysis was conducted on an XBridge C18 column (150 mm×30 mm internal diameter, 5 μm packing diameter) at ambient temperature.

The solvents employed were:

A=10 mM ammonium bicarbonate in water adjusted to pH 10 with ammonia solution.

B=acetonitrile.

For each of the mass-directed autopreparative purifications, irrespective of the modifier used, the gradient employed was dependent upon the retention time of the particular compound undergoing purification as recorded in the analytical LCMS, and was as follows:

For compounds with an analytical LCMS retention time below 0.6 minutes the following gradient was used:

Time Flow Rate (minutes) (mL/min) % A % B 0 40 99 1 1 40 99 1 10 40 70 30 11 40 1 99 15 40 1 99

For compounds with an analytical LCMS retention time between 0.6 and 0.9 minutes the following gradient was used:

Time Flow Rate (minutes) (mL/min) % A % B 0 40 85 15 1 40 85 15 10 40 45 55 11 40 1 99 15 40 1 99

For compounds with an analytical LCMS retention time between 0.9 and 1.2 minutes the following gradient was used:

Time Flow Rate (minutes) (mL/min) % A % B 0 40 70 30 1 40 70 30 10 40 15 85 11 40 1 99 15 40 1 99

For compounds with an analytical LCMS retention time between 1.2 and 1.4 minutes the following gradient was used:

Time Flow Rate (minutes) (mL/min) % A % B 0 40 50 50 1 40 50 50 10 40 1 99 11 40 1 99 15 40 1 99

For compounds with an analytical LCMS retention time greater than 1.4 minutes (LCMS method A) or greater than 3.6 minutes (LCMS method B) the following gradient was used:

Time Flow Rate (minutes) (mL/min) % A % B 0 40 20 80 1 40 20 80 10 40 1 99 11 40 1 99 15 40 1 99

The UV detection was an averaged signal from wavelength of 210 nm to 350 nm and mass spectra were recorded on a mass spectrometer using alternate-scan positive and negative mode electrospray ionization.

The chemical names were generated using ACD Name Pro version 6.02 from Advanced Chemistry Development, Inc.

4-((6-Methoxy-2-(4-methoxyphenyl)benzo[b]thiophen-3-yl)oxy)phenol can be prepared according to the process described by Palkowitz, Alan David, U.S. Pat. No. 5,492,922A.

3-Bromo-2-(4-bromophenyl)-6-methoxybenzo[b]thiophene 1-oxide can be prepared according to the process described by Zhihui Qin et al. J. Med. Chem. 2007, 50, 2682-2692.

3-Bromo-2-(4-fluorophenyl)-6-methoxybenzo[b]thiophene 1-oxide can be prepared according to the process described by Hong Liu et al. Chem. Res. Toxicol. 2005, 18, 162-173.

tert-Butyl 2-(2-(benzyloxy)ethoxy)acetate

KO^(t)Bu (3.24 g, 29 mmol) was added to a stirred solution of 2-(benzyloxy)ethanol (commercially available from for example Aldrich) (4 g, 26 mmol) in tBuOH (30 mL) and the mixture was stirred at room temperature for 2 hours. Tert-butyl 2-bromoacetate (commercially available from for example Aldrich) (7 mL, 47 mmol) was then added, and the mixture was stirred at room temperature overnight. The mixture was diluted with DCM (50 mL) and washed with water (2×50 mL) and then brine (2×50 mL). The organic extract was dried using a hydrophobic frit and concentrated under reduced pressure. The crude product was purified by chromatography on silica (330 g cartridge) using a gradient elution from 0% to 100% methyl tert-butyl ether in cyclohexane to afford the title compound (724 mg, 2.3 mmol, 9% yield). LCMS RT=1.10 min, ES+ve m/z 267.4 [M+H]⁺

tert-Butyl 2-(2-hydroxyethoxy)acetate

A mixture of tert-butyl 2-(2-(benzyloxy)ethoxy)acetate (724 mg, 2.3 mmol) and 10% w/w palladium on carbon (365 mg, 0.34 mmol) in ethanol (10 mL) was stirred at room temperature under an atmosphere of hydrogen for 1.5 hours. The palladium on carbon was filtered through celite and the filtrate evaporated under reduced pressure to afford the title compound (349 mg, 1.8 mmol, 78% yield). LCMS RT=0.61 min, ES+ve m/z 263.4 [M+H]⁺.

tert-Butyl 2-(2-(tosyloxy)ethoxy)acetate

Tosyl chloride (578 mg, 3.0 mmol) was added to a cooled solution (0° C.) of tert-butyl 2-(2-hydroxyethoxy)acetate (349 mg, 1.8 mmol) in pyridine (4 mL). The reaction was stirred at room temperature for 16 hours. The reaction mixture was partitioned between ethyl acetate (50 mL) and 2M aqueous HCl (40 mL). The organic extract was separated, washed with 2M aqueous HCl (40 mL), followed by saturated sodium bicarbonate (50 mL) and brine (50 mL). The organic extract was then dried (hydrophobic frit) and concentrated under reduced pressure to afford the title compound (618 mg, 1.50 mmol, 84% yield). LCMS RT=1.14 min, ES+ve m/z 348.0 [M+NH₄]⁺.

tert-Butyl 2-(2-(2-(benzyloxy)ethoxy)ethoxy)acetate

KO^(t)Bu (20 mL, 20 mmol) was added to a stirred solution of 2-(2-(benzyloxy)ethoxy)ethanol (commercially available from for example Aldrich) (2.74 mL, 15 mmol) in tBuOH (30 mL) and the mixture was stirred under a nitrogen atmosphere at room temperature for 2 hours. The reaction mixture was cooled to 0° C., tert-butyl 2-bromoacetate (commercially available from for example Aldrich) (4 mL, 28 mmol) was added and the mixture stirred at room temperature overnight. The reaction mixture was then concentrated, and partitioned between water (50 mL) and DCM (50 mL). The organic layer was separated and the aqueous layer was extracted further with DCM (50 mL). The combined organic layers were dried using a hydrophobic frit and concentrated under reduced pressure. The product was purified by chromatography on silica using a gradient elution from 0% to 100% methyl tert-butyl ether in cyclohexane to afford the title compound (3.56 g, 11 mmol, 74% yield). LCMS RT=1.11 min, ES+ve m/z 311.4 [M+H]⁺, 328.4 [M+NH₄]⁺.

tert-Butyl 2-(2-(2-hydroxyethoxy)ethoxy)acetate

A mixture of tert-butyl 2-(2-(2-(benzyloxy)ethoxy)ethoxy)acetate (7.97 g, 25 mmol) and 10% w/w palladium on carbon (2.68 g, 2.5 mmol) in ethanol (100 mL) was stirred at room temperature under an atmosphere of hydrogen for 1.5 hours. The mixture was filtered through celite and the filtrate evaporated under reduced pressure to afford the title compound (5.45 g, 22 mmol, 88% yield). LCMS RT=0.65 min, ES+ve m/z 238.1 [M+NH₄]⁺. ¹H NMR (400 MHz, CDCl₃) δ=3.98 (s, 2H), 3.74-3.64 (m, 6H), 3.62-3.55 (m, 2H), 2.77 (t, J=6.0 Hz, 1H), 1.44 (s, 9H).

tert-Butyl 2-(2-(2-(tosyloxy)ethoxy)ethoxy)acetate

Tosyl chloride (commercially available from for example Aldrich) (3.60 g, 19 mmol) was added to a cooled solution (0° C.) of tert-butyl 2-(2-(2-hydroxyethoxy)ethoxy)acetate (2.72 g, 11 mmol) in pyridine (25 mL). The reaction was slowly warmed to room temperature and stirred for 16 hours. The reaction mixture was partitioned between ethyl acetate (30 mL) and 2M aqueous HCl (30 mL). The organic extract was separated, washed with 2M aqueous HCl (30 mL), dried using a hydrophobic frit, and concentrated under reduced pressure. The product was purified by chromatography on silica (330 g cartridge) using a gradient elution from 0% to 100% methyl tert-butyl ether in cyclohexane to afford the title compound (1.71 g, 4.5 mmol, 40% yield). LCMS RT=1.13 min, ES+ve m/z 375.3 [M+H]⁺.

tert-Butyl 1-phenyl-2,5,8,11-tetraoxatridecan-13-oate

Potassium tert-butoxide (commercially available from for example Aldrich) (7.71 g, 69 mmol) was added to a stirred solution of 2-(2-(2-(benzyloxy)ethoxy)ethoxy)ethanol (commercially available from for example Fluorochem) (15 g, 62 mmol) in tert-butanol (200 mL) and the reaction mixture was stirred at room temperature for 2 h. The reaction mixture was cooled to 0° C., tert-butyl 2-bromoacetate (commercially available from for example Aldrich) (17 mL, 112 mmol) was added, and the mixture was stirred at room temperature overnight. DCM (300 mL) was added and the organic phase was washed with water (300 mL) and then brine (2×200 mL). The organic extract was dried using a hydrophobic frit and concentrated under reduced pressure to give the crude product as a yellow oil. The product was purified by chromatography on silica using a gradient elution from 0% to 100% methyl tert-butyl ether in cyclohexane to afford the title compound (13.3 g, 38 mmol, 60% yield). LCMS RT=1.10 min, ES+ve m/z 372.4 [M+NH₄]⁺.

tert-Butyl 2-(2-(2-(2-hydroxyethoxy)ethoxy)ethoxy)acetate

A mixture of tert-butyl 1-phenyl-2,5,8,11-tetraoxatridecan-13-oate (13.3 g, 38 mmol) and palladium on carbon (10% w/w, 11.4 g, 11 mmol) in ethanol (200 mL) was stirred at room temperature under an atmosphere of hydrogen for 1.5 h. The mixture was filtered through celite and the filtrate was evaporated under reduced pressure to afford the title compound (9.74 g, 37 mmol, 98% yield) as a yellow oil. ¹H NMR (400 MHz, DMSO-d₆) δ=4.54 (s, 1H), 3.99 (s, 2H), 3.60-3.40 (m, 12H), 1.43 (s, 9H).

tert-Butyl 2-(2-(2-(2-(tosyloxy)ethoxy)ethoxy)ethoxy)acetate

Tosyl chloride (commercially available from for example Aldrich) (11.9 g, 63 mmol) was added to a cooled solution (0° C.) of tert-butyl 2-(2-(2-(2-hydroxyethoxy)ethoxy)ethoxy)acetate (9.74 g, 37 mmol) in pyridine (150 mL). The reaction was stirred at room temperature for 16 h. The reaction mixture was partitioned between ethyl acetate (300 mL) and aqueous HCl (2M, 300 mL). The organic extract was washed with further aqueous HCl (2M, 300 mL), saturated K₂CO₃ (100 mL) and brine (100 mL). The organic extract was dried using MgSO₄ and concentrated under reduced pressure to afford the title compound (10.3 g, 25 mmol, 67% yield) as a yellow oil. LCMS RT=1.14 min, ES+ve 436.2 [M+NH₄]⁺.

2-(2-(3-(Benzyloxy)propoxy)ethoxy)ethanol

Sodium hydride (60% w/w in mineral oil) (350 mg, 8.8 mmol) was added to a mixture of 2,2′-oxydiethanol (commercially available from for example Aldrich) (2.32 g, 22 mmol) and ((3-bromopropoxy)methyl)benzene (commercially available from for example Aldrich) (0.77 mL, 4.4 mmol) in DMF (10 mL). The reaction mixture was stirred at room temperature for 3 hours. An additional aliquot of sodium hydride, (60% w/w in mineral oil) (350 mg, 8.8 mmol) was added and the reaction mixture was stirred at room temperature for 16 hours. The mixture was partitioned between ethyl acetate (50 mL) and water (50 mL). The organic layer was separated, dried using a hydrophobic frit and concentrated under reduced pressure. The product was purified by chromatography on silica (50 g cartridge) using a gradient elution from 0% to 25% MeOH in DCM to afford the title compound (648 mg, 2.6 mmol, 58% yield). LCMS RT=0.78 min, ES+ve m/z 255.1 [M+H]⁺

tert-Butyl 1-phenyl-2,6,9,12-tetraoxatetradecan-14-oate

KO^(t)Bu (315 mg, 2.8 mmol) was added to a stirred solution of 2-(2-(3-(benzyloxy)propoxy)ethoxy)ethanol (648 mg, 2.6 mmol) in tBuOH (8 mL) and the mixture was stirred at room temperature for 2 hours. Tert-butyl 2-bromoacetate (commercially available from for example Aldrich) (0.68 mL, 4.6 mmol) was added, and the mixture was stirred at room temperature overnight. Further aliquots of KO^(t)Bu (315 mg, 2.8 mmol) and tert-butyl 2-bromoacetate (0.68 mL, 4.6 mmol) were added and the reaction was stirred at room temperature for 6 hours. A final aliquot of tert-butyl 2-bromoacetate (0.68 mL, 4.6 mmol) was added and the reaction was stirred for 16 hours. The reaction mixture was partitioned between water (50 mL) and DCM (70 mL). The organic layer was separated, dried using a hydrophobic frit and concentrated under reduced pressure. The product was purified by chromatography on silica using a gradient elution from 0% to 100% methyl tert-butyl ether in cyclohexane, followed by 0% to 20% MeOH in cyclohexane to afford the title compound (438 mg, 1.2 mmol, 47% yield). LCMS RT=1.16 min, ES+ve m/z 369.5 [M+H]⁺

tert-Butyl 2-(2-(2-(3-hydroxypropoxy)ethoxy)ethoxy)acetate

A mixture of tert-butyl 1-phenyl-2,6,9,12-tetraoxatetradecan-14-oate (418 mg, 1.13 mmol) and 10% w/w palladium on carbon (0.05 g, 0.47 mmol) in ethanol (5 mL) was stirred under an atmosphere of hydrogen for 2 hours. The mixture was filtered through celite and the filtrate evaporated under reduced pressure to afford the title compound (314 mg, 1.1 mmol, 99% yield). ¹H NMR (400 MHz, CDCl₃) δ=4.03 (s, 2H), 3.84-3.75 (m, 2H), 3.74-3.58 (m, 10H), 2.58-2.43 (m, 1H), 1.87-1.78 (m, 2H), 1.48 (s, 9H).

tert-Butyl 2-(2-(2-(3-(tosyloxy)propoxy)ethoxy)ethoxy)acetate

Tosyl chloride (commercially available from for example Aldrich) (430 mg, 2.3 mmol) was added to a cooled solution (0° C.) of tert-butyl 2-(2-(2-(3-hydroxypropoxy)ethoxy)ethoxy)acetate (314 mg, 1.1 mmol) in pyridine (5 mL). The reaction was slowly warmed to room temperature and stirred for 16 hours. The reaction mixture was partitioned between ethyl acetate (30 mL) and saturated aqueous sodium bicarbonate (30 mL). The organic extract was washed with additional saturated aqueous sodium bicarbonate (2×30 mL), brine (30 mL), dried using a hydrophobic frit and concentrated under reduced pressure. The crude product was purified by chromatography on silica using a gradient elution from 0% to 100% methyl tert-butyl ether in cyclohexane to afford the title compound (310 mg, 0.72 mmol, 64% yield). LCMS RT=1.14 min, ES+ve m/z 450.3 [M+NH₄]⁺.

(2S,4R)-tert-Butyl 2-((4-bromobenzyl)carbamoyl)-4-hydroxypyrrolidine-1-carboxylate

An ice-cooled mixture of (2S,4R)-1-(tert-butoxycarbonyl)-4-hydroxypyrrolidine-2-carboxylic acid (commercially available from for example Aldrich) (7.95 g, 34 mmol) and (4-bromophenyl)methanamine (commercially available from for example FluroChem) (6.4 g, 34 mmol) in DMF (200 mL) was treated with DIPEA (18 mL, 103 mmol) and then with HATU (14.4 g, 38 mmol) and the mixture was stirred at ambient temperature for 30 minutes. The reaction was quenched with water (200 mL) and extracted with ethyl acetate (2×200 mL). The combined organic layers were washed with saturated aqueous sodium bicarbonate (2×300 mL), water (100 mL), brine (200 mL), dried over magnesium sulphate and evaporated to dryness. The product was purified by chromatography on silica using a gradient elution from 0% to 10% methanol in DCM to afford the title compound (12.9 g, 32 mmol, 94% yield). LCMS RT=0.87 min, ES+ve m/z 399.2/401.2 [M+H]⁺.

(2S,4R)-tert-Butyl 4-hydroxy-2-((4-(4-methylthiazol-5-yl)benzyl)carbamoyl)pyrrolidine-1-carboxylate

A mixture of (2S,4R)-tert-butyl 2-((4-bromobenzyl)carbamoyl)-4-hydroxypyrrolidine-1-carboxylate (12.9 g, 32 mmol), 4-methylthiazole (commercially available from for example Aldrich) (5.9 mL, 65 mmol), palladium(II) acetate (commercially available from for example Aldrich) (0.145 g, 0.65 mmol) and potassium acetate (6.34 g, 65 mmol) in N-methyl-2-pyrrolidone (80 mL) was stirred at 120° C. under nitrogen for 18 hours. Water (100 ml) was added and the product was extracted with ethyl acetate (4×300 mL). The combined organic phase was washed with brine (5×200 mL), dried over magnesium sulfate and evaporated to dryness. The product was purified by chromatography on silica using a gradient elution from 0% to 10% methanol in DCM to afford the title compound (8 g, 19 mmol, 59% yield). LCMS RT=0.75 min, ES+ve m/z 418.4 [M+H]⁺.

(2S,4R)-4-Hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride

(2S,4R)-tert-Butyl 4-hydroxy-2-((4-(4-methylthiazol-5-yl)benzyl)carbamoyl)pyrrolidine-1-carboxylate (8 g, 19 mmol) was dissolved in methanol (30 mL) and DCM (20 mL) and treated with HCl in dioxane (4M, 8 mL, 32 mmol). The reaction mixture was stirred at ambient temperature for 2 hours. The solvent was removed under reduced pressure and the residue was triturated with DCM, filtered and dried under reduced pressure to afford the title compound (6.7 g, 19 mmol, 99% yield). LCMS RT=0.49 min, ES+ve m/z 318.3 [M+H]⁺.

tert-Butyl ((S)-1-((2S,4R)-4-hydroxy-2-((4-(4-methylthiazol-5-yl)benzyl)carbamoyl)pyrrolidin-1-yl)-3-methyl-1-oxobutan-2-yl)carbamate

A stirred mixture of (2S,4R)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (125 mg, 0.35 mmol) and (S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanoic acid (commercially available from for example Aldrich) (77 mg, 0.35 mmol) in DMF (0.9 mL) was treated with DIPEA (0.22 mL, 1.3 mmol) and then with HATU (134 mg, 0.35 mmol) and the mixture was stirred at ambient temperature for 1 hour. The reaction mixture was subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (120 mg, 0.23 mmol, 72% yield). LCMS RT=0.87 min, ES+ve m/z 517.3 [M+H]⁺.

(2S,4R)-1-((S)-2-Amino-3-methylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride

A solution of tert-butyl ((S)-1-((2S,4R)-4-hydroxy-2-((4-(4-methylthiazol-5-yl)benzyl)carbamoyl)pyrrolidin-1-yl)-3-methyl-1-oxobutan-2-yl)carbamate (287 mg, 0.56 mmol) in THF (5 mL) was treated with HCl in 1,4-dioxan (4M, 10 mL, 40 mmol) and stirred at ambient temperature for 2 hours. The mixture was evaporated to dryness to afford the title compound (224 mg, 0.49 mmol, quantitative). LCMS RT=0.55 min, ES+ve m/z 417.3 [M+H]⁺.

tert-Butyl ((S)-1-cyclopentyl-2-((2S,4R)-4-hydroxy-2-((4-(4-methylthiazol-5-yl)benzyl)carbamoyl)pyrrolidin-1-yl)-2-oxoethyl)carbamate

HATU (260 mg, 0.68 mmol) was added to a solution of (2S,4R)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (200 mg, 0.57 mmol), (S)-2-((tert-butoxycarbonyl)amino)-2-cyclopentylacetic acid (commercially available from for example Fluorochem) (180 mg, 0.74 mmol) and DIPEA (0.40 mL, 2.3 mmol) in DMF (2 mL). The reaction was stirred at room temperature for 30 min, and was subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (200 mg, 0.37 mmol, 65% yield). LCMS RT=0.94 min, ES+ve m/z 543.4 [M+H]⁺.

(2S,4R)-1-((S)-2-Amino-2-cyclopentylacetyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride

A solution of tert-butyl ((S)-1-cyclopentyl-2-((2S,4R)-4-hydroxy-2-((4-(4-methylthiazol-5-yl)benzyl)carbamoyl)pyrrolidin-1-yl)-2-oxoethyl)carbamate (200 mg, 0.37 mmol) was suspended in DCM (1 mL) and treated with HCl in dioxane (4 M, 1 mL, 4.0 mmol), followed by MeOH (0.5 mL). The reaction mixture was stirred at room temperature for 3 hours. The mixture was evaporated to dryness to afford the title compound (160 mg, 0.33 mmol, 89% yield). LCMS RT=0.61 min, ES+ve m/z 443.6 [M+H]⁺.

(2S,4R)-1-((S)-2-Amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride

A stirred mixture of (2S,4R)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (70 mg, 0.20 mmol) and (S)-2-((tert-butoxycarbonyl)amino)-3,3-dimethylbutanoic acid (commercially available from for example Fluka) (50 mg, 0.22 mmol) in DMF (1 mL) was treated with DIPEA (0.14 mL, 0.79 mmol) and then with HATU (90 mg, 0.24 mmol), and stirred at ambient temperature for 30 minutes. The reaction mixture was subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to give the intermediate boc-protected product. The intermediate was then dissolved in a mixture of dichloromethane (0.5 mL) and methanol (0.1 mL) and treated with HCl in 1,4-dioxane (4M, 0.25 mL, 1.0 mmol). After stirring at ambient temperature for 1 hour, the reaction mixture was evaporated to dryness and the residue triturated to a solid with dichloromethane and dried under vacuum to afford the title compound (76 mg, 0.16 mmol, 82% yield). LCMS RT=0.58 min, ES+ve m/z 431.2 [M+H]⁺.

4-(Oxazol-5-yl)benzonitrile

A mixture of 4-formylbenzonitrile (commercially available from for example Aldrich) (5.32 g, 41 mmol), 1-((isocyanomethyl)sulfonyl)-4-methylbenzene (commercially available from for example Aldrich) (8.83 g, 45 mmol) and potassium carbonate (7.3 g, 53 mmol) in methanol (200 mL) was stirred at ambient temperature for 80 minutes. The mixture was then evaporated to dryness; the residue was treated with saturated aqueous sodium bicarbonate (100 mL) and extracted with dichloromethane (3×100 mL). The combined organics were washed with brine (75 mL), passed through a hydrophobic frit and then evaporated to dryness to afford the title compound (7.19 g, 42 mmol, quantitative). LCMS RT=0.75 min, ES+ve m/z 171 [M+H]⁺.

(4-(Oxazol-5-yl)phenyl)methanamine

Under an atmosphere of nitrogen, an ice-cooled mixture of 4-(oxazol-5-yl)benzonitrile (900 mg, 5.29 mmol) and cobalt(II) chloride hexahydrate (commercially available from for example Aldrich) (1.8 g, 7.9 mmol) in methanol (50 mL) was treated portion-wise over 5 minutes with sodium borohydride (1 g, 26 mmol). The mixture was stirred for 30 minutes and then treated with water (50 mL) and concentrated aqueous ammonia (20 mL). The mixture was extracted with chloroform (3×150 mL), the combined organics were evaporated to dryness and the product was purified by chromatography on silica using a gradient elution from 0% to 30% methanol in dichloromethane (+0.1% triethylamine) to afford the title compound (580 mg, 3.3 mmol, 63% yield). LCMS RT=0.35 min, ES+ve m/z 175 [M+H]⁺.

(2S,4R)-tert-Butyl 4-hydroxy-2-((4-(oxazol-5-yl)benzyl)carbamoyl)pyrrolidine-1-carboxylate

To a stirred solution of (2S,4R)-1-(tert-butoxycarbonyl)-4-hydroxypyrrolidine-2-carboxylic acid (0.66 g, 2.9 mmol) in dry DMF (20 mL) were added (4-(oxazol-5-yl)phenyl)methanamine (0.5 g, 2.9 mmol) and DIPEA (1 mL, 5.7 mmol). This solution was then ice-cooled and HATU (1.09 g, 2.9 mmol) was added. The reaction mixture was stirred with cooling for an additional hour then treated with water (30 mL) and extracted with ethyl acetate (3×100 mL). The combined organic phase was washed with saturated aqueous sodium bicarbonate (60 mL), brine (60 mL), dried over magnesium sulfate, filtered and evaporated to dryness. The product was purified by chromatography on silica using a gradient elution from 0% to 25% methanol in dichloromethane to afford the title compound (758 mg, 1.96 mmol, 68% yield). LCMS RT=0.73 min, ES+ve m/z 388 [M+H]⁺.

(2S,4R)-4-Hydroxy-N-(4-(oxazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride

A solution of (2S,4R)-tert-butyl 4-hydroxy-2-((4-(oxazol-5-yl)benzyl)carbamoyl)pyrrolidine-1-carboxylate (2.74 g, 7.1 mmol) in methanol (10 mL) and dichloromethane (15 mL) was treated with hydrochloric acid (4 M in 1,4-dioxane) (8.8 mL, 35 mmol) and the mixture was stirred at ambient temperature for 24 hours. The mixture was evaporated to dryness. The residue was suspended in methanol, filtered and dried under vacuum to afford the title compound (2.24 g, 6.9 mmol, 98% yield). LCMS RT=0.44 min, ES+ve m/z 288 [M+H]⁺.

(2S,4R)-1-((S)-2-Amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(oxazol-5-yl)benzyl)pyrrolidine-2-carboxamide, Hydrochloride

HATU (141 mg, 0.371 mmol) was added to a solution of (S)-2-((tert-butoxycarbonyl)amino)-3,3-dimethylbutanoic acid (86 mg, 0.37 mmol), (2S,4R)-4-hydroxy-N-(4-(oxazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (100 mg, 0.31 mmol) and DIPEA (0.162 mL, 0.93 mmol) in DMF (4 mL). The reaction was stirred for 45 min at room temperature. The reaction mixture was partitioned between EtOAc (20 mL) and water (20 mL). The aqueous phase was back extracted with EtOAc and the organic phase washed with brine (10 mL). The combined organic extracts were dried using an hydrophobic frit and concentrated under reduced pressure. The residue was purified by chromatography on silica using a gradient elution from 0% to 10% methanol in dichloromethane to give the required intermediate (132 mg). HCl in dioxane (4M, 0.386 mL, 1.54 mmol) was added to a solution of the intermediate (132 mg) dissolved in DCM (2 mL) and MeOH (2 mL). The mixture was stirred at room temperature for 4 h and was then concentrated under reduced pressure to afford the title compound (95 mg, 0.22 mmol, 70% yield) as a beige solid. LCMS RT=0.53 min, ES+ve m/z 401.4 [M+H]⁺.

tert-Butyl 2-(2-(2-(2-(4-((6-methoxy-2-(4-methoxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)ethoxy)ethoxy)ethoxy)acetate

A mixture of 4-((6-methoxy-2-(4-methoxyphenyl)benzo[b]thiophen-3-yl)oxy)phenol (200 mg, 0.53 mmol), tert-butyl 2-(2-(2-(2-(tosyloxy)ethoxy)ethoxy)ethoxy)acetate (265 mg, 0.63 mmol), K₂CO₃ (219 mg, 1.59 mmol) in DMF (3 mL) was heated at 85° C. for 16 h. A further aliquot of tert-butyl 2-(2-(2-(2-(tosyloxy)ethoxy)ethoxy)ethoxy)acetate (265 mg, 0.63 mmol) was added and the reaction heated at 85° C. for further 24 h. The reaction was cooled to room temperature and partitioned between EtOAc (25 mL) and water (25 mL). The organic extract was washed with brine (25 mL), dried using a hydrophobic frit and concentrated under reduced pressure. The product was purified by chromatography on silica using a gradient elution from 0% to 50% EtOAc in cyclohexane to afford the title compound (245 mg, 0.39 mmol, 74% yield). LCMS RT=1.48 min, ES+ve m/z 625.4 [M+H]⁺.

2-(2-(2-(2-(4-((6-Hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)ethoxy)ethoxy)ethoxy)acetic acid

Under an atmosphere of nitrogen, an ice-cooled solution of tert-butyl 2-(2-(2-(2-(4-((6-methoxy-2-(4-methoxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)ethoxy)ethoxy)ethoxy)acetate (245 mg, 0.39 mmol) in dry dichloromethane (5 mL) was treated with propane-1-thiol (commercially available from for example Aldrich) (0.178 mL, 1.97 mmol) and then with aluminium chloride (commercially available from for example Aldrich) (418 mg, 3.1 mmol). The reaction mixture was stirred at room temperature for 16 h. A further aliquot of propane-1-thiol (0.178 mL, 1.96 mmol) and aluminium chloride (418 mg, 3.1 mmol) were added and the reaction was stirred at room temperature for further 24 h. Aqueous HCl (2M, 20 mL) was added and the product was extracted with EtOAc (2×25 mL). The organic extracts were combined, dried using a hydrophobic frit and concentrated under reduced pressure. The residue was purified by SPE on aminopropyl (NH₂): the column was first washed with MeOH (3 column volumes) and the product released by elution with ammonia in methanol (2M, 3 column volumes). The ammonia fraction was concentrated under reduced pressure. The product was subjected to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (33 mg, 0.061 mmol, 16% yield) as a colourless glass. LCMS RT=0.90 min, ES+ve m/z 541.2 [M+H]⁺.

Example 1 (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-((6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide

HATU (commercially available from for example Aldrich) (19 mg, 0.050 mmol) was added to a mixture of 2-(2-(2-(2-(4-((6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)ethoxy)ethoxy)ethoxy)acetic acid (22 mg, 0.041 mmol), (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl) pyrrolidine-2-carboxamide, hydrochloride (23 mg, 0.049 mmol) and DIPEA (commercially available from for example Aldrich) (0.05 mL, 0.29 mmol) in DMF (0.8 mL). The reaction was left standing at room temperature for 25 minutes. The reaction mixture was directly subjected to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (8 mg, 0.008 mmol, 21% yield) as a colourless glass. LCMS RT=1.02 min, ES+ve m/z 953.5 [M+H]⁺.

Example 2 (2S,4R)-4-Hydroxy-1-((S)-14-(4-((6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)-2-isopropyl-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide

HATU (20 mg, 0.053 mmol) was added to a mixture of 2-(2-(2-(2-(4-((6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)ethoxy)ethoxy)ethoxy)acetic acid (20 mg, 0.037 mmol) (2S,4R)-1-((S)-2-amino-3-methylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (20 mg, 0.044 mmol) and DIPEA (0.05 mL, 0.29 mmol) in DMF (0.8 mL). The reaction was left standing at room temperature for 25 minutes. The reaction mixture was directly subjected to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (9 mg, 0.0096 mmol, 26% yield) as colourless glass. LCMS RT=0.98 min, ES+ve m/z 939.5 [M+H]⁺.

Example 3 (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-((6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(oxazol-5-yl)benzyl)pyrrolidine-2-carboxamide

HATU (16 mg, 0.042 mmol) was added to a mixture of (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(oxazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (18 mg, 0.041 mmol), 2-(2-(2-(2-(4-((6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)ethoxy)ethoxy)ethoxy)acetic acid (15 mg, 0.028 mmol) and DIPEA (0.024 mL, 0.14 mmol) in DMF (0.8 mL). The reaction was stirred for 45 min at room temperature. The reaction mixture was directly subjected to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (3 mg, 0.003 mmol, 12% yield) as a white solid. LCMS RT=0.98 min, ES+ve m/z 923.2, 924.3 [M+H]⁺.

Example 4 (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-((2-(4-hydroxyphenyl)-6-methoxybenzo[b]thiophen-3-yl)oxy)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide

Under an atmosphere of nitrogen, an ice-cooled solution of tert-butyl 2-(2-(2-(2-(4-((6-methoxy-2-(4-methoxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)ethoxy)ethoxy)ethoxy)acetate (290 mg, 0.46 mmol) in dry dichloromethane (15 mL) was treated with propane-1-thiol (0.210 mL, 2.3 mmol) and aluminium chloride (495 mg, 3.7 mmol). The reaction was stirred at room temperature for 6 h. Aqueous HCl (1M, 10 mL) were added and the product was extracted with EtOAc (50 mL). The organic extract was dried using a hydrophobic frit and concentrated under reduced pressure. The residue was purified by SPE on aminopropyl (NH₂): the column was first washed with MeOH (3 column volumes) and the product released by elution with ammonia in methanol (2M, 4 column volumes). The ammonia fraction was concentrated under reduced pressure and the residue was partitioned between EtOAc (25 mL) and aqueous HCl (1M, 25 mL). The organic extract was dried using a hydrophobic frit and concentrated under reduced pressure to give a yellow residue as (130 mg).

70 mg of the obtained residue were dissolved in DMF (0.8 mL) and treated with (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (73 mg, 0.16 mmol) and DIPEA (0.15 mL, 0.859 mmol). HATU (60 mg, 0.16 mmol) was added to the stirred reaction mixture and the reaction was left standing at room temperature for 25 minutes. The solution was directly subjected to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (20 mg, 0.021 mmol, 5% yield) as a yellow solid. LCMS RT=1.19 min, ES+ve m/z 967.4 [M+H]⁺.

4-((6-Methoxy-2-phenylbenzo[b]thiophen-3-yl)oxy)phenol

Hydroquinone (commercially available from for example Aldrich) (133 mg, 1.207 mmol) was dissolved in DMF (2 mL). NaH (60% w/w in mineral oil) (20 mg, 0.5 mmol) was added slowly followed by 3-bromo-2-(4-bromophenyl)-6-methoxybenzo[b]thiophene 1-oxide (100 mg, 0.24 mmol). The reaction mixture was stirred at room temperature for 3 h. Water (10 mL) was added and the product was extracted with EtOAc (30 mL). The organic extract was dried using a hydrophobic frit and concentrated under reduced pressure. The residue was purified by chromatography on silica using a gradient elution from 0% to 100% ethyl acetate in cyclohexane followed by a 0% to 20% methanol in ethyl acetate gradient elution to afford a yellow solid (186 mg). This solid was dissolved in THF (5 mL) and treated with LiAlH₄ in THF (1M, 1.3 mL, 1.3 mmol).

The reaction was stirred at ambient temperature for 1 h. Aqueous NaOH (50%, 50 mL) was carefully added and the mixture was partitioned between EtOAc (50 mL) and water (50 mL). 2M HCl was added to reach pH 1 in the aqueous phase. The organic extract was dried using a hydrophobic frit and concentrated under reduced pressure. The product was purified by chromatography on silica using a gradient elution from 0% to 100% ethyl acetate in cyclohexane to afford the title compound (90 mg, 0.26 mmol, 80% pure, 86% yield) as a white solid. LCMS RT=1.29 min, ES+ve m/z 349.3 [M+H]⁺.

tert-Butyl 2-(2-(2-(2-(4-((6-methoxy-2-phenylbenzo[b]thiophen-3-yl)oxy)phenoxy)ethoxy)ethoxy)ethoxy)acetate

A mixture of 4-((6-methoxy-2-phenylbenzo[b]thiophen-3-yl)oxy)phenol (90 mg, 0.26 mmol), tert-butyl 2-(2-(2-(2-(tosyloxy)ethoxy)ethoxy)ethoxy)acetate (216 mg, 0.517 mmol), K₂CO₃ (107 mg, 0.78 mmol) in DMF (2 mL) was heated at 85° C. for 16 h. The reaction was cooled to room temperature and partitioned between EtOAc (30 mL) and water (30 mL). The organic layer was dried using a hydrophobic frit and concentrated under reduced pressure. The product was purified by chromatography on silica using a gradient elution from 0% to 50% ethyl acetate in cyclohexane to afford the title compound (104 mg, 0.18 mmol, 68% yield) as a yellow oil. LCMS RT=1.50 min, ES+ve m/z 617.3 [M+Na]⁺.

Example 5 (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-((6-hydroxy-2-phenylbenzo[b]thiophen-3-yl)oxy)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide

Under an atmosphere of nitrogen, an ice-cooled solution of tert-butyl 2-(2-(2-(2-(4-((6-methoxy-2-phenylbenzo[b]thiophen-3-yl)oxy)phenoxy)ethoxy)ethoxy)ethoxy)acetate (104 mg, 0.175 mmol) in dry dichloromethane (10 mL) was treated with propane-1-thiol (0.048 mL, 0.525 mmol) followed by aluminium chloride (117 mg, 0.87 mmol). The reaction was stirred at room temperature for 3 h. A further aliquot of propane-1-thiol (0.048 mL, 0.53 mmol) and aluminium chloride (117 mg, 0.874 mmol) was added and the suspension was sonicated for 10 minutes to help solubilise the reactants. The reaction was then stirred at room temperature for 3 h. Aqueous HCl (1M, 10 mL) was added and the product was extracted with EtOAc (50 mL). The organic extract was dried using a hydrophobic frit and concentrated under reduced pressure. The residue was purified by SPE on aminopropyl (NH₂): the column was first washed with MeOH (3 column volumes) and the product released by elution with ammonia in methanol (2M, 4 column volumes). The ammonia fraction was concentrated under reduced pressure and the residue was partitioned between EtOAc (25 mL) and aqueous HCl (1M, 25 mL). The organic extract was dried using a hydrophobic frit and concentrated under reduced pressure to give a yellow residue (44 mg). This residue was dissolved in DMF (0.8 mL) and treated with (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (59 mg, 0.13 mmol) and DIPEA (0.1 mL, 0.57 mmol). HATU (47 mg, 0.12 mmol) was added to the solution which was stirred at room temperature for 10 min. The solution was then directly subjected to purification by mass-directed automated preparative HPLC (formic acid modifier gradient) to afford the title compound (10 mg, 10.7 μmol, 6% yield) as a colourless glass. LCMS RT=1.20 min, ES+ve m/z 937.6 [M+H]⁺.

2-(4-Bromophenyl)-3-(4-(tert-butoxy)phenoxy)-6-methoxybenzo[b]thiophene 1-oxide

4-(tert-Butoxy)phenol (2.56 g, 15.41 mmol) was dissolved in DMF (70 mL). NaH, in mineral oil (60% w/w, 0.840 g, 21 mmol) was added slowly followed by 3-bromo-2-(4-bromophenyl)-6-methoxybenzo[b]thiophene 1-oxide (commercially available from for example Aldrich) (5.8 g, 14 mmol). The reaction mixture was stirred at room temperature for 3 h. Water (100 mL) followed by aqueous HCl (2M, 20 mL) were added and the product was extracted with EtOAc (200 mL). The organic extract was dried using MgSO₄ and concentrated under reduced pressure to afford the title compound (5.8 g, 11.6 mmol, 83% yield). LCMS RT=1.41 min, ES+ve m/z 499.1/501.1 [M+H]⁺.

4-((2-(4-Bromophenyl)-6-methoxybenzo[b]thiophen-3-yl)oxy)phenol

TMSCl (commercially available from for example Aldrich) (3.84 mL, 30 mmol) was added to a solution of 2-(4-bromophenyl)-3-(4-(tert-butoxy)phenoxy)-6-methoxybenzo[b]thiophene 1-oxide (1.5 g, 3 mmol) and triphenylphosphine (2.75 g, 10.5 mmol) in THF (30 mL). The reaction mixture was stirred under reflux conditions for 3 h. The reaction was cooled to room temperature and water (100 mL) was added. The intermediate was extracted with EtOAc (200 mL). The organic extract was dried using a hydrophobic frit and concentrated under reduced pressure. The intermediate was purified by chromatography on silica using a gradient elution from 0% to 50% ethyl acetate in cyclohexane to afford a yellow oil. The oil was dissolved in DCM (15 mL) and treated with HCl in dioxane (4M, 7.5 mL, 30 mmol). The reaction was heated for 3 h at 40° C. The solvent was removed under reduced pressure and the residue was partitioned between EtOAc (150 mL) and brine (150 mL). The organic extract was dried using a hydrophobic frit and concentrated under reduced pressure. The product was purified by chromatography on silica using a gradient elution from 0% to 35% ethyl acetate in cyclohexane to afford the title compound (1 g, 2.3 mmol, 78% yield) as a white solid. LCMS RT=1.41 min, ES+ve m/z 427.1/429.1 [M+H]⁺.

tert-Butyl 2-(2-(2-(2-(4-((2-(4-bromophenyl)-6-methoxybenzo[b]thiophen-3-yl)oxy)phenoxy)ethoxy)ethoxy)ethoxy)acetate

A mixture of 4-((2-(4-bromophenyl)-6-methoxybenzo[b]thiophen-3-yl)oxy)phenol (1 g, 2.340 mmol), tert-butyl 2-(2-(2-(2-(tosyloxy)ethoxy)ethoxy)ethoxy)acetate (2 g, 4.8 mmol), K₂CO₃ (1 g, 7.2 mmol) in DMF (2 mL) was heated at 85° C. for 48 h. The reaction was cooled to room temperature and partitioned between EtOAc (100 mL) and water (100 mL). The organic layer was dried using a hydrophobic frit and concentrated under reduced pressure. The product was purified by chromatography on silica using a gradient elution from 0% to 50% ethyl acetate in cyclohexane to afford the title compound (1.41 g, 2.1 mmol, 89% yield) as a yellow oil. LCMS RT=1.61 min, ES+ve m/z 690.4/692.4 [M+NH₄]⁺.

Example 6 (2S,4R)-1-((S)-14-(4-((2-(4-Bromophenyl)-6-hydroxybenzo[b]thiophen-3-yl)oxy)phenoxy)-2-(tert-butyl)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide

Under an atmosphere of nitrogen, an ice-cooled solution of tert-butyl 2-(2-(2-(2-(4-((2-(4-bromophenyl)-6-methoxybenzo[b]thiophen-3-yl)oxy)phenoxy)ethoxy)ethoxy)ethoxy)acetate (225 mg, 0.33 mmol) in dry DCM (10 mL) was treated with propane-1-thiol (0.091 mL, 1.0 mmol) followed by aluminium chloride (223 mg, 1.7 mmol). The reaction was then stirred at room temperature for 5 h. Aqueous HCl (1M, 10 mL) was added and the product was extracted with EtOAc (50 mL). The organic extract was dried using a hydrophobic frit and concentrated under reduced pressure. The residue was dissolved in DMF (3 mL) and treated with DIPEA (0.3 mL, 1.718 mmol) and (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (234 mg, 0.5 mmol). HATU (191 mg, 0.5 mmol) was added and the reaction was stirred at room temperature for 10 min. The solution was then subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (72 mg, 0.071 mmol, 21% yield) as a white solid. LCMS RT=1.30 min, ES+ve m/z 1015.3/1017.3 [M+H]⁺.

3-(4-(tert-Butoxy)phenoxy)-2-(4-fluorophenyl)-6-methoxybenzo[b]thiophene 1-oxide

4-(tert-Butoxy)phenol (393 mg, 2.37 mmol) was dissolved in DMF (15 mL). NaH in mineral oil (60% w/w, 172 mg, 4.3 mmol) was added slowly followed by 3-bromo-2-(4-fluorophenyl)-6-methoxybenzo[b]thiophene 1-oxide (760 mg, 2.2 mmol). The reaction mixture was stirred at room temperature for 2.5 h. Water (200 mL) was added and the product was extracted with EtOAc (200 mL). Aqueous HCl (2M) was added until the pH of aqueous phase was 1 and the aqueous phase was extracted with EtOAc (200 mL). The combined organic extracts were washed with brine (300 mL), dried using a hydrophobic frit and concentrated under reduced pressure. The product was purified by chromatography on silica using a gradient elution from 0% to 50% ethyl acetate in dichloromethane to afford the title compound (815 mg, 1.86 mmol, 86% yield) as a yellow solid. LCMS RT=1.32 min, ES+ve m/z 439.3 [M+H]⁺.

3-(4-(tert-Butoxy)phenoxy)-2-(4-fluorophenyl)-6-methoxybenzo[b]thiophene

LiAlH₄ in THF (1M, 3.72 mL, 3.7 mmol) was added to a mixture of 3-(4-(tert-butoxy)phenoxy)-2-(4-fluorophenyl)-6-methoxybenzo[b]thiophene 1-oxide (815 mg, 1.86 mmol) in THF (15 mL). The reaction was stirred at ambient temperature for 1.5 h. Aqueous NaOH (50%, 10 mL) was carefully added and the mixture was partitioned between EtOAc (100 mL) and water (100 mL). The aqueous phase was further extracted with EtOAc (3×100 mL). The organic extracts were combined, dried using a hydrophobic fit and concentrated under reduced pressure. The product was purified by chromatography on silica using a gradient elution from 0% to 50% dichloromethane in cyclohexane to afford the title compound (560 mg, 1.33 mmol, 71% yield) as a colourless gum. LCMS RT=1.61 min, ES+ve m/z 423.0 [M+H]⁺.

4-((2-(4-Fluorophenyl)-6-methoxybenzo[b]thiophen-3-yl)oxy)phenol

3-(4-(tert-Butoxy)phenoxy)-2-(4-fluorophenyl)-6-methoxybenzo[b]thiophene (560 mg, 1.33 mmol) was dissolved in 1,4-dioxane (5 mL). HCl in dioxane (4M, 5 mL, 20 mmol) was added and the reaction mixture was stirred overnight at 60° C. The mixture was concentrated under reduced pressure. The residue was dissolved in acetonitrile and concentrated under reduced pressure to afford the title compound (450 mg, 1.2 mmol, 93% yield). LCMS RT=1.30 min, ES+ve m/z 367.2 [M+H]⁺.

tert-Butyl 2-(2-(2-(2-(4-((2-(4-fluorophenyl)-6-methoxybenzo[b]thiophen-3-yl)oxy)phenoxy)ethoxy)ethoxy)ethoxy)acetate

A mixture of 4-((2-(4-fluorophenyl)-6-methoxybenzo[b]thiophen-3-yl)oxy)phenol (450 mg, 1.228 mmol), tert-butyl 2-(2-(2-(2-(tosyloxy)ethoxy)ethoxy)ethoxy)acetate (1.028 g, 2.46 mmol), K₂CO₃ (509 mg, 3.68 mmol) in DMF (6 mL) was heated at 80° C. for 72 hours. The reaction was cooled to room temperature and partitioned between EtOAc (50 mL) and water (50 mL). The organic extract was washed with brine (50 mL), dried using a hydrophobic frit and concentrated under reduced pressure. The product was purified by chromatography on silica using a gradient elution from 0% to 50% ethyl acetate in cyclohexane to afford the title compound (600 mg, 0.98 mmol, 80% yield) as a colourless gum. LCMS RT=1.51 min, ES+ve m/z 635 [M+Na]⁺.

Example 7 (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-((2-(4-fluorophenyl)-6-hydroxybenzo[b]thiophen-3-yl)oxy)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide

Under an atmosphere of nitrogen, an ice-cooled solution of tert-butyl 2-(2-(2-(2-(4-((2-(4-fluorophenyl)-6-methoxybenzo[b]thiophen-3-yl)oxy)phenoxy)ethoxy)ethoxy)ethoxy)acetate (240 mg, 0.39 mmol) in dry DCM (10 mL) was treated with propane-1-thiol (0.107 mL, 1.18 mmol) followed by aluminium chloride (261 mg, 1.96 mmol). The reaction was then stirred at room temperature for 4 h. A further aliquot of aluminium chloride (130 mg, 0.98 mmol) was added and the reaction was stirred at room temperature for a further hour. Aqueous HCl (1M, 10 mL) was added and the product was extracted with EtOAc (50 mL). The organic extract was dried using a hydrophobic frit and concentrated under reduced pressure. The residue was purified by SPE on aminopropyl (NH₂): the column was first washed with MeOH (3 column volumes) and the product released by elution with ammonia in methanol (2M, 4 column volumes). The ammonia fraction was concentrated under reduced pressure and the residue was partitioned between EtOAc (25 mL) and aqueous HCl (1M, 25 mL). The organic extract was dried using a hydrophobic frit and concentrated under reduced pressure to give a yellow residue (126 mg). This residue was dissolved in DMF (1.6 mL) and treated with DIPEA (0.342 mL, 1.96 mmol) and (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (163 mg, 0.35 mmol). HATU (132 mg, 0.347 mmol) was added and the reaction was stirred at room temperature for 10 min. The solution was then directly subjected to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (47 mg, 0.049 mmol, 13% yield) as an off-white solid. LCMS RT=1.21 min, ES+ve m/z 955.6 [M+H]⁺.

(4-Fluorophenyl)(6-methoxy-2-(4-methoxyphenyl)benzo[b]thiophen-3-yl)methanone

Under an atmosphere of nitrogen, an ice-cooled suspension of 6-methoxy-2-(4-methoxyphenyl)benzo[b]thiophene (commercially available from for example Aldrich) (10 g, 37 mmol) in anhydrous dichloromethane (250 mL) was treated with aluminium chloride (5.9 g, 44 mmol) and then with 4-fluorobenzoyl chloride (commercially available from for example Aldrich) (5.2 mL, 44 mmol). The mixture was stirred at 0° C. for 3 days and then treated with 1M aqueous hydrochloric acid (200 mL) and stirred for 20 minutes. The mixture was subsequently treated with dichloromethane (200 mL) and 1M aqueous hydrochloric acid (200 mL) and separated. The aqueous phase was extracted with additional dichloromethane (2×150 mL) and the organics were combined and evaporated to dryness. The product was purified by chromatography on silica using a gradient elution from 0% to 25% ethyl acetate in cyclohexane to afford the title compound (12.7 g, 32 mmol, 87% yield). LCMS RT=1.40 min, ES+ve m/z 393.3 [M+H]⁺.

(4-(2-(2-(2-Hydroxyethoxy)ethoxy)ethoxy)phenyl)(6-methoxy-2-(4-methoxyphenyl)benzo[b]thiophen-3-yl) methanone

Sodium hydride (60% w/w in mineral oil) (64 mg, 1.6 mmol) was added to an ice-cooled solution of 2,2′-(ethane-1,2-diylbis(oxy))diethanol (commercially available from for example Aldrich) (670 mg, 4.5 mmol) in DMF (3.5 mL). The reaction was stirred at 0° C. for 15 min and (4-fluorophenyl)(6-methoxy-2-(4-methoxyphenyl)benzo[b]thiophen-3-yl)methanone (350 mg, 0.89 mmol) was then added. The reaction mixture was warmed to room temperature and stirred for a further 3 hours. The reaction mixture was partitioned between DCM (40 mL) and water (40 mL). The mixture was separated and the aqueous phase was extracted with additional DCM (40 mL). The combined organic extracts were evaporated to dryness and the product was purified by chromatography on silica (50 g cartridge) using a gradient elution from 0% to 25% MeOH in DCM to afford the title compound (453 mg, 0.87 mmol, 93% yield). LCMS RT=1.17 min, ES+ve m/z 523.3 [M+H]⁺.

(4-(2-(2-(2-(2-Hydroxyethoxy)ethoxy)ethoxy)ethoxy)phenyl)(6-methoxy-2-(4-methoxyphenyl)benzo[b]thiophen-3-yl)methanone

Under an atmosphere of nitrogen, an ice-cooled solution of (4-fluorophenyl)(6-methoxy-2-(4-methoxyphenyl)benzo[b]thiophen-3-yl)methanone (1.72 g, 4.4 mmol) and 2,2′-((oxybis(ethane-2,1-diyl))bis(oxy))diethanol (commercially available from for example Aldrich) (4.26 g, 22 mmol) in dry DMF (20 mL) was treated with sodium hydride (60% w/w in mineral oil) (316 mg, 7.9 mmol) and the mixture was stirred with ice cooling for 15 minutes then allowed to warm to ambient temperature. After 2 hours the mixture was treated with water (50 mL) and dichloromethane (70 mL). The mixture was separated and the aqueous phase was extracted with dichloromethane (20 mL). The combined organics were evaporated to dryness and the product was purified by chromatography on silica using a gradient elution from 0% to 25% methanol in dichloromethane to afford the title compound (2.34 g, 4.1 mmol, 94% yield). LCMS RT=1.18 min, ES+ve m/z 567 [M+F]⁺.

tert-Butyl 2-(2-(2-(2-(4-(6-methoxy-2-(4-methoxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethoxy)ethoxy)ethoxy)acetate

Sodium hydride, 60% w/w in mineral oil (69 mg, 1.7 mmol) was added to an ice-cooled solution of (4-(2-(2-(2-hydroxyethoxy)ethoxy)ethoxy)phenyl)(6-methoxy-2-(4-methoxyphenyl)benzo[b]thiophen-3-yl)methanone (450 mg, 0.86 mmol) in DMF (3.3 mL). The reaction was stirred at 0° C. for 1 hour and tert-butyl 2-bromoacetate (commercially available from for example Aldrich) (0.25 mL, 1.7 mmol) was added. The reaction was warmed to room temperature and stirred for a further 3 hours. The reaction mixture was partitioned between ethyl acetate (30 mL) and water (30 mL). The organic layer was separated, washed with brine (30 mL), passed through a hydrophobic frit and evaporated to dryness. The product was purified by chromatography on silica (50 g cartridge) using a gradient elution from 0% to 100% ethyl acetate in cyclohexane to afford the title compound (330 mg, 0.52 mmol, 60% yield). LCMS RT=1.40 min, ES-ve m/z 637.3 [M+H]⁺, 659.3 [M+Na]⁺.

2-(2-(2-(2-(4-(6-Hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethoxy)ethoxy)ethoxy)acetic acid 2-(2-(2-(2-(4-(6-Hydroxy-2-(4-methoxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethoxy)ethoxy)ethoxy)acetic acid 2-(2-(2-(2-(4-(2-(4-Hydroxyphenyl)-6-methoxybenzo[b]thiophene-3-carbonyl)phenoxy)ethoxy)ethoxy)ethoxy)acetic acid

A cooled solution (0° C.) of tert-butyl 2-(2-(2-(2-(4-(6-methoxy-2-(4-methoxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethoxy)ethoxy)ethoxy)acetate (330 mg, 0.518 mmol) in dry DCM (7 mL) was treated with propane-1-thiol (commercially available from for example Aldrich) (0.188 mL, 2.1 mmol) and then with aluminium chloride (commercially available from for example Aldrich) (290 mg, 2.2 mmol). The reaction was warmed to room temperature, and stirred for 3 hours. A further aliquot of aluminium chloride (290 mg, 2.2 mmol) was added, and the reaction mixture was stirred at room temperature overnight. The reaction mixture was treated cautiously with 2M aqueous HCl (10 mL) and THF (20 mL). The organic layer was separated and the aqueous layer was extracted with DCM (2×20 mL). The combined organic layers were dried using a hydrophobic frit and concentrated under reduced pressure. The crude product was dissolved in DMSO (4 mL) and subjected to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the three products:

2-(2-(2-(2-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethoxy)ethoxy)ethoxy)acetic acid (140 mg, 0.25 mmol, 49% yield). LCMS RT=0.84 min, ES+ve m/z 553.3 [M+H]⁺.

2-(2-(2-(2-(4-(6-hydroxy-2-(4-methoxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethoxy)ethoxy)ethoxy)acetic acid (16 mg, 0.028 mmol, 5% yield). LCMS RT=0.99 min, ES+ve m/z 567.3 [M+H]⁺.

2-(2-(2-(2-(4-(2-(4-hydroxyphenyl)-6-methoxybenzo[b]thiophene-3-carbonyl)phenoxy)ethoxy)ethoxy)ethoxy)acetic acid (58 mg, 0.10 mmol, 20% yield). LCMS RT=1.04 min, ES+ve m/z 567.3 [M+H]⁺.

14-(4-(6-Hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-3,6,9,12-tetraoxatetradecan-1-oic acid 14-(4-(6-Hydroxy-2-(4-methoxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-3,6,9,12-tetraoxatetradecan-1-oic acid 14-(4-(2-(4-Hydroxyphenyl)-6-methoxybenzo[b]thiophene-3-carbonyl)phenoxy)-3,6,9,12-tetraoxatetradecan-1-oic acid

Under an atmosphere of nitrogen, an ice-cooled solution of tert-butyl 14-(4-(6-methoxy-2-(4-methoxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-3,6,9,12-tetraoxatetradecan-1-oate (480 mg, 0.71 mmol) in dry dichloromethane (10 mL) was treated with propane-1-thiol (commercially available from for example Aldrich) (0.319 mL, 3.5 mmol) and then with aluminium chloride (564 mg, 4.2 mmol). After 3 hours the mixture was treated cautiously with 2M aqueous hydrochloric acid (10 mL) and then evaporated to dryness. The product was subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the three title compounds:

14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl) phenoxy)-3,6,9,12-tetraoxatetradecan-1-oic acid (220 mg, 0.37 mmol, 52% yield). LCMS RT=0.87 min, ES+ve m/z 597 [M+H]⁺.

14-(4-(6-hydroxy-2-(4-methoxyphenyl)benzo[13]thiophene-3-carbonyl) phenoxy)-3,6,9,12-tetraoxatetradecan-1-oic acid (24 mg, 0.039 mmol, 5.6% yield). LCMS RT=0.99 min, ES+ve m/z 610 [M+H]⁺.

14-(4-(2-(4-hydroxyphenyl)-6-methoxybenzo[b]thiophene-3-carbonyl)phenoxy)-3,6,9,12-tetraoxatetradecan-1-oic acid (53 mg, 0.087 mmol, 12% yield). LCMS RT=1.05 min, ES+ve m/z 610 [M+H]⁺.

Example 8 (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide

HATU (27 mg, 0.071 mmol) was added to a mixture of (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (38 mg, 0.081 mmol), 2-(2-(2-(2-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethoxy)ethoxy)ethoxy)acetic acid (30 mg, 0.054 mmol) and DIPEA (0.095 mL, 0.54 mmol) in DMF (0.8 mL). The reaction was stirred at room temperature for 30 min, and was then subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (16 mg, 0.017 mmol, 31% yield). LCMS RT=0.97 min, ES+ve m/z 966.4 [M+H]⁺.

Using a method analogous to that for (2S,4R)-1-((S)-2-(tert-butyl)-14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide the following compounds were prepared:

Structure Example Name (R₁) Yield RT [M + H]+ Example 9 (2S,4R)-4-Hydroxy-1- Me 67% 0.88 min 923.4 ((S)-14-(4-(6-hydroxy-2- (4- hydroxyphenyl)benzo[b] thiophene-3- carbonyl)phenoxy)-2- methyl-4-oxo-6,9,12- trioxa-3-azatetradecan- 1-oyl)-N-(4-(4- methylthiazol-5- yl)benzyl)pyrrolidine-2- carboxamide Example 10 (2S,4R)-1-((S)-2-Ethyl- Et 74% 0.91 min 937.5 14-(4-(6-hydroxy-2-(4- hydroxyphenyl)benzo[b] thiophene-3- carbonyl)phenoxy)-4- oxo-6,9,12-trioxa-3- azatetradecan-1-oyl)-4- hydroxy-N-(4-(4- methylthiazol-5- yl)benzyl)pyrrolidine-2- carboxamide Example 11 (2S,4R)-4-Hydroxy-1- ^(i)Pr 65% 0.93 min 951.5 ((S)-14-(4-(6-hydroxy-2- (4- hydroxyphenyl)benzo[b] thiophene-3- carbonyl)phenoxy)-2- isopropyl-4-oxo-6,9,12- trioxa-3-azatetradecan- 1-oyl)-N-(4-(4- methylthiazol-5- yl)benzyl)pyrrolidine-2- carboxamide Example 12 (2S,4R)-1-((S)-2- Cyclopropyl-14-(4-(6- hydroxy-2-(4- hydroxyphenyl)benzo[b]

70% 0.91 min 949.3 thiophene-3- carbonyl)phenoxy)-4- oxo-6,9,12-trioxa-3- azatetradecan-1-oyl)-4- hydroxy-N-(4-(4- methylthiazol-5- yl)benzyl)pyrrolidine-2- carboxamide Example 13 (2S,4R)-1-((S)-2- Cyclopentyl-14-(4-(6- hydroxy-2-(4- hydroxyphenyl)benzo[b] thiophene-3- carbonyl)phenoxy)-4-

72% 0.97 min 977.4 oxo-6,9,12-trioxa-3- azatetradecan-1-yl)-4- hydroxy-N-(4-(4- methylthiazol-5- yl)benzyl)pyrrolidine-2- carboxamide Example 14 (2S,4R)-4-Hydroxy-1- ((S)-14-(4-(6-hydroxy-2- (4- hydroxyphenyl)benzo[b] thiophene-3- carbonyl)phenoxy)-2-

64% 0.97 min 965.5 isobutyl-4-oxo-6,9,12- trioxa-3-azatetradecan- 1-oyl)-N-(4-(4- methylthiazol-5- yl)benzyl)pyrrolidine-2- carboxamide

Example 15 (2S,4R)-4-Hydroxy-1-((S)-17-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-2-isopropyl-4-oxo-6,9,12,15-tetraoxa-3-azaheptadecan-1-oyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide

A solution of 14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-3,6,9,12-tetraoxatetradecan-1-oic acid (18 mg, 0.030 mmol) in DMF (0.7 mL) was treated with DIPEA (0.021 mL, 0.12 mmol) and (2S,4R)-1-((S)-2-amino-3-methylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (22 mg, 0.048 mmol) and then with HATU (14 mg, 0.036 mmol) and the mixture was stirred for 30 minutes. The product was subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (25 mg, 0.025 mmol, 83% yield). LCMS RT=0.94 min, ES+ve m/z 995.5 [M+H]⁺.

Example 16 (2S,4R)-1-((S)-2-(tert-Butyl)-17-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12,15-tetraoxa-3-azaheptadecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide

A solution of 14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-3,6,9,12-tetraoxatetradecan-1-oic acid (18 mg, 0.030 mmol) in DMF (0.7 mL) was treated with DIPEA (0.021 mL, 0.12 mmol) and (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (23 mg, 0.048 mmol) and then with HATU (14 mg, 0.036 mmol) and the mixture was stirred for 30 minutes. The product was subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (22 mg, 0.022 mmol, 72% yield). LCMS RT=0.98 min, ES+ve m/z 1009.5 [M+H]⁺.

Example 17 (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-(2-(4-hydroxyphenyl)-6-methoxybenzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide

HATU (27 mg, 0.071 mmol) was added to a mixture of (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride) (38 mg, 0.081 mmol), 2-(2-(2-(2-(4-(2-(4-hydroxyphenyl)-6-methoxybenzo[b]thiophene-3-carbonyl)phenoxy)ethoxy)ethoxy)ethoxy)acetic acid (31 mg, 0.054 mmol) and DIPEA (0.095 mL, 0.54 mmol) in DMF (0.8 mL). The reaction was stirred at room temperature for 30 min, and was then subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (15 mg, 0.015 mmol, 28% yield). LCMS RT=1.14 min, ES+ve m/z 979.5 [M+H]⁺.

Example 18 (2S,4R)-1-((S)-2-(Tert-butyl)-14-(4-(6-hydroxy-2-(4-methoxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide

HATU (11 mg, 0.028 mmol) was added to a mixture of (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (15 mg, 0.032 mmol), 2-(2-(2-(2-(4-(6-hydroxy-2-(4-methoxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethoxy) ethoxy) ethoxy) acetic acid (13 mg, 0.022 mmol) and DIPEA (0.038 mL, 0.22 mmol) in DMF (0.6 mL). The reaction was stirred at room temperature for 30 min, and was then subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (9 mg, 0.009 mmol, 43% yield). LCMS RT=1.09 min, ES+ve m/z 979.5 [M+H]⁺.

Example 19 (2S,4R)-1-((S)-2-(tert-Butyl)-17-(4-(6-hydroxy-2-(4-methoxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12,15-tetraoxa-3-azaheptadecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide

A mixture of 14-(4-(2-(4-hydroxyphenyl)-6-methoxybenzo[b]thiophene-3-carbonyl)phenoxy)-3,6,9,12-tetraoxatetradecan-1-oic acid (20 mg, 0.033 mmol) and (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (23 mg, 0.049 mmol) in DMF (0.7 mL) was treated with DIPEA (0.023 mL, 0.13 mmol) and then with HATU (15 mg, 0.039 mmol) and stirred at ambient temperature for 15 minutes. The product was subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (14 mg, 0.014 mmol, 42% yield). LCMS RT=1.09 min, ES+ve m/z 1023.5 [M+H]⁺.

Example 20 (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(oxazol-5-yl)benzyl)pyrrolidine-2-carboxamide

HATU (21 mg, 0.056 mmol) was added to a mixture of (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(oxazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (29 mg, 0.065 mmol), 2-(2-(2-(2-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethoxy)ethoxy)ethoxy)acetic acid (24 mg, 0.043 mmol) and DIPEA (0.076 mL, 0.43 mmol) in DMF (0.8 mL). The reaction was stirred at room temperature for 30 min and was then subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (26 mg, 0.028 mmol, 64% yield). LCMS RT=0.94 min, ES+ve m/z 935.6 [M+H]⁺.

(4-Fluorophenyl)(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)methanone

Under an atmosphere of nitrogen, an ice-cooled solution of (4-fluorophenyl)(6-methoxy-2-(4-methoxyphenyl)benzo[b]thiophen-3-yl)methanone (5 g, 13 mmol) in dry DCM (50 mL) was treated cautiously with boron tribromide in DCM (1M, 38 mL, 38 mmol), and the mixture was stirred with cooling for 2 hours. The mixture was treated cautiously with water (100 mL) and then with DCM (50 mL) and MeOH (15 mL). The mixture was partitioned and the aqueous phase was extracted with 10% MeOH in DCM (100 mL). The combined organic extracts were evaporated to dryness and the product was purified by chromatography on silica using a gradient elution from 0% to 100% ethyl acetate in DCM to afford the title compound (3.95 g, 11 mmol, 85% yield). LCMS RT=0.98 min, ES+ve m/z 365.2 [M+H]⁺.

(6-(Benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophen-3-yl)(4-fluorophenyl)methanone

A solution of (4-fluorophenyl)(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)methanone (2.58 g, 7.1 mmol) in DMF (25 mL) was treated with sodium carbonate (3.00 g, 28.3 mmol) and then with benzyl bromide (2.53 mL, 21 mmol). The mixture was heated gradually to 75° C. and heated at that temperature for 6 hours, then at 60° C. overnight. The cooled mixture was treated with DCM (150 mL) and water (100 mL) and the organic phase was separated. The aqueous phase was extracted with additional DCM (50 mL) and the combined organic layers were evaporated to dryness. The product was purified by chromatography on silica using a gradient elution from 0% to 20% ethyl acetate in cyclohexane to afford the title compound (2.97 g, 5.5 mmol, 77% yield). LCMS RT=1.59 min, ES+ve m/z 545.2 [M+H]⁺.

(6-(Benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophen-3-yl)(4-(2-(2-hydroxyethoxy)ethoxy)phenyl)methanone

Sodium hydride, 60% w/w in mineral oil (40 mg, 0.99 mmol) was added to an ice-cooled solution of 2,2′-oxydiethanol (commercially available from for example Aldrich) (292 mg, 2.8 mmol) in dry DMF (3 mL), and the mixture was stirred for 30 min. (6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophen-3-yl)(4-fluorophenyl)methanone (300 mg, 0.55 mmol) was added, and the reaction mixture was warmed to ambient temperature, and stirred for a further 18 hours. The mixture was treated with water (50 mL) and DCM (50 mL), and the organic phase was separated. The aqueous phase was extracted with additional DCM (50 mL). The combined organic extracts were evaporated to dryness and the product was purified by chromatography on silica (50 g cartridge) using a gradient elution from 0% to 25% MeOH in DCM to afford the title compound (260 mg, 0.41 mmol, 75% yield). LCMS RT=1.45 min, ES+ve m/z 631.4 [M+H]⁺.

tert-Butyl 2-(2-(2-(4-(6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethoxy)ethoxy)acetate

Sodium hydride, 60% w/w in mineral oil (25 mg, 0.634 mmol) was added to a cooled solution (0° C.) of (6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophen-3-yl)(4-(2-(2-hydroxyethoxy)ethoxy)phenyl)methanone (200 mg, 0.32 mmol) in DMF (1.2 mL). The reaction was stirred at 0° C. for 1 hour and tert-butyl 2-bromoacetate (commercially available from for example Aldrich) (0.094 mL, 0.63 mmol) was added. The reaction was warmed to room temperature and stirred for 3 hours. The reaction mixture was partitioned between ethyl acetate (30 mL) and water (30 mL). The organic layer was separated, washed with brine (30 mL), dried using a hydrophobic frit and concentrated under reduced pressure. The product was purified by chromatography on silica (50 g cartridge) using a gradient elution from 0% to 100% ethyl acetate in cyclohexane to afford the title compound (200 mg, 0.23 mmol, 74% yield). LCMS RT=1.59 min, ES+ve m/z 745.5 [M+H]⁺.

2-(2-(2-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethoxy)ethoxy)acetic acid

A mixture of tert-butyl 2-(2-(2-(4-(6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethoxy)ethoxy)acetate (200 mg, 0.27 mmol), 10% w/w palladium on carbon (29 mg, 0.027 mmol), ammonium formate (339 mg, 5.4 mmol) and water (0.19 mL, 11 mmol) in DMF (2.6 mL) was heated at 50° C. for 2 hours. The reaction mixture was filtered through celite, washed with ethyl acetate, and the filtrate was concentrated under reduced pressure. The crude material was dissolved in TFA (1.5 mL) and was stirred at room temperature for 10 min. The reaction mixture was concentrated, and a 1:1 mixture of 25% aqueous HCl/THF (3 mL) was added. The crude mixture was then subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (51 mg, 0.10 mmol, 37% yield). LCMS RT=0.84 min, ES+ve m/z 509.3 [M+H]⁺.

Example 21 (2S,4R)-4-Hydroxy-1-((S)-2-(2-(2-(2-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethoxy)ethoxy)acetamido)-3,3-dimethylbutanoyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide

HATU (25 mg, 0.066 mmol) was added to a mixture of (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (31 mg, 0.066 mmol), 2-(2-(2-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethoxy)ethoxy)acetic acid (26 mg, 0.051 mmol) and DIPEA (0.089 mL, 0.51 mmol) in DMF (0.6 mL). The reaction was stirred at room temperature for 30 min, and was then subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (33 mg, 0.035 mmol, 69% yield) LCMS RT=0.96 min, ES+ve m/z 921.4 [M+H]⁺.

tert-Butyl (2-(4-(6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethyl)(methyl)carbamate

Sodium hydride, 60% w/w in mineral oil (54 mg, 1.35 mmol) was added to a cooled solution (0° C.) of tert-butyl (2-hydroxyethyl)(methyl)carbamate (commercially available from for example Chem-impex) (225 mg, 1.29 mmol) in DMF (3 mL) and the mixture was stirred at 0° C. for 15 min. (6-(Benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophen-3-yl)(4-fluorophenyl)methanone (350 mg, 0.64 mmol) was added and the reaction was slowly warmed to room temperature and stirred for 18 hours. The mixture was treated cautiously with water (40 mL) and ethyl acetate (40 mL). The organic phase was separated and the aqueous phase was extracted with additional ethyl acetate (40 mL). The combined organic extracts were washed with water (40 mL), brine (40 mL) and evaporated under reduced pressure to afford the title compound (445 mg, 0.64 mmol, 99% yield). LCMS RT=1.63 min, ES+ve m/z 700.5 [M+H]⁺, 722.3 [M+Na]⁺.

(6-(Benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophen-3-yl)(4-(2-(methylamino)ethoxy)phenyl)methanone, hydrochloride

HCl in dioxane (4 M, 1.6 mL, 6.4 mmol) was added to a solution of tert-butyl (2-(4-(6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethyl)(methyl)carbamate (445 mg, 0.64 mmol) in DCM (2 mL) and the mixture was stirred at room temperature for 1 hour. The solvent was removed under reduced to afford the title compound (400 mg, 0.63 mmol, 98% yield). LCMS RT=1.16 min, ES+ve m/z 600.3 [M+H]⁺.

tert-Butyl 2-(2-(2-((2-(4-(6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethyl)(methyl)amino)ethoxy)ethoxy)acetate

A vial was charged with (6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophen-3-yl)(4-(2-(methylamino)ethoxy)phenyl)methanone, hydrochloride (140 mg, 0.22 mmol), tert-butyl 2-(2-(2-(tosyloxy)ethoxy)ethoxy)acetate (99 mg, 0.26 mmol), DIPEA (0.15 mL, 0.88 mmol) and DMF (1.5 mL). The vial was sealed and the reaction was heated at 80° C. for 18 hours. Additional tert-butyl 2-(2-(2-(tosyloxy)ethoxy)ethoxy)acetate (99 mg, 0.26 mmol) was added and the reaction was stirred at 80° C. for a further 24 hours. The reaction was cooled to room temperature and the mixture was then subjected directly to purification by mass-directed automated preparative HPLC (ammonium bicarbonate modifier) to afford the title compound (85 mg, 0.11 mmol, 48% yield). LCMS RT=1.31 min, ES+ve m/z 802.4 [M+H]⁺.

2-(2-(2-((2-(4-(6-Hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethyl)(methyl)amino)ethoxy)ethoxy)acetic acid, hydrochloride

A mixture of tert-butyl 2-(2-(2-((2-(4-(6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethyl)(methyl)amino)ethoxy)ethoxy)acetate (80 mg, 0.1 mmol), 10% w/w palladium on carbon (11 mg, 0.01 mmol), ammonium formate (126 mg, 2 mmol) and water (0.072 mL, 4 mmol) in DMF (1 mL) was heated at 50° C. for 1 hour. The reaction mixture was filtered through celite, washed with ethyl acetate, and the filtrate was concentrated under reduced pressure. The crude material was then dissolved in TFA (1 mL) and was stirred at room temperature for 10 min. The reaction mixture was concentrated, and a 1:1 mixture of 25% aqueous HCl/THF (3 mL) was added. The crude mixture was then subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (37 mg, 0.061 mmol, 62% yield). LCMS RT=0.68 min, ES+ve m/z 566.3 [M+H]⁺.

Example 22 (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-12-methyl-4-oxo-6,9-dioxa-3,12-diazatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide

HATU (25 mg, 0.066 mmol) was added to a mixture of (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (35 mg, 0.075 mmol), 2-(2-(2-((2-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethyl)(methyl)amino) ethoxy)ethoxy)acetic acid, hydrochloride (30 mg, 0.050 mmol) and DIPEA (0.087 mL, 0.5 mmol) in DMF (0.8 mL). The reaction was stirred at room temperature for 30 min, and was then subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier). The product contained a small amount of impurity, and was therefore dissolved in a 1:1 mixture of MeOH and DMSO (1 mL), and subjected to purification by mass-directed automated preparative HPLC using an ammonium bicarbonate modifier to afford the title compound (24 mg, 0.025 mmol, 49% yield). LCMS RT=0.80 min, ES+ve m/z 978.5 [M+H]⁺.

tert-Butyl 15-(4-(6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-13-methyl-3,6,9-trioxa-13-azapentadecan-1-oate

A vial was charged with (6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophen-3-yl)(4-(2-(methylamino)ethoxy)phenyl)methanone, hydrochloride (150 mg, 0.24 mmol), tert-butyl 2-(2-(2-(3-(tosyloxy)propoxy)ethoxy)ethoxy)acetate (143 mg, 0.33 mmol), DIPEA (0.165 mL, 0.94 mmol) and DMF (1.4 mL). The vial was sealed and the reaction was heated at 80° C. for 18 hours. The reaction was cooled to room temperature and the mixture was then subjected directly to purification by mass-directed automated preparative HPLC (ammonium bicarbonate modifier) to afford the title compound (90 mg, 0.11 mmol, 44% yield). LCMS RT=1.32 min, ES+ve m/z 860.5 [M+H]⁺.

15-(4-(6-Hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-13-methyl-3,6,9-trioxa-13-azapentadecan-1-oic acid, hydrochloride

A mixture of tert-butyl 15-(4-(6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-13-methyl-3,6,9-trioxa-13-azapentadecan-1-oate (90 mg, 0.11 mmol), 10% w/w palladium on carbon (11 mg, 0.01 mmol), ammonium formate (132 mg, 2.1 mmol) and water (0.075 mL, 4.2 mmol) in DMF (1 mL) was heated at 50° C. for 1 hour. The reaction mixture was filtered through celite, washed with ethyl acetate, and the filtrate was concentrated under reduced pressure. The crude material was dissolved in TFA (1 mL) and was stirred at room temperature for 10 min. The reaction mixture was concentrated, and a 1:1 mixture of 25% aqueous HCl/THF (2 mL) was added. The crude mixture was then subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (60 mg, 0.091 mmol, 87% yield). LCMS RT=0.69 min, ES+ve m/z 624.4 [M+H]⁺.

Example 23 (2S,4R)-1-((S)-2-(tert-Butyl)-18-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-16-methyl-4-oxo-6,9,12-trioxa-3,16-diazaoctadecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide

HATU (37 mg, 0.098 mmol) was added to a mixture of (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (53 mg, 0.11 mmol), 15-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-13-methyl-3,6,9-trioxa-13-azapentadecan-1-oic acid, hydrochloride (50 mg, 0.076 mmol) and DIPEA (0.132 mL, 0.76 mmol) in DMF (0.8 mL). The reaction was stirred at room temperature for 30 min, and was then subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier). The product contained a small amount of impurity, and was therefore dissolved in a 1:1 mixture of MeOH and DMSO (1 mL), and subjected to purification by mass-directed automated preparative HPLC using an ammonium bicarbonatemodifier to afford the title compound (38 mg, 0.037 mmol, 48% yield). LCMS RT=0.82 min, ES+ve m/z 1036.5 [M+H]⁺.

(6-(Benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophen-3-yl)(4-(4-(2-(2-hydroxyethoxy)ethyl)piperazin-1-yl)phenyl)methanone

A solution of (6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophen-3-yl)(4-fluorophenyl)methanone (320 mg, 0.59 mmol) in NMP (3 mL) was sealed and heated in a Biotage “Initiator” microwave at 160° C. for 1 hr. The cooled product was subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (181 mg, 0.26 mmol, 44% yield). LCMS RT=1.19 min, ES+ve m/z 699 [M+H]⁺.

tert-Butyl 2-(2-(2-(4-(4-(6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophene-3-carbonyl)phenyl)piperazin-1-yl)ethoxy)ethoxy)acetate

Under an atmosphere of nitrogen, a solution of (6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophen-3-yl)(4-(4-(2-(2-hydroxyethoxy)ethyl)piperazin-1-yl)phenyl)methanone (120 mg, 0.17 mmol) in DMF (5 mL) was treated with tert-butyl bromoacetate (0.1 mL, 0.69 mmol) and then with sodium hydride (60% in mineral oil) (41 mg, 1.03 mmol) and stirred at ambient temperature overnight. The mixture was treated with 5% aqueous ammonium chloride (30 mL) and extracted with dichloromethane (30 mL). The organic fraction was evaporated to dryness and the product was subjected to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (80 mg, 0.098 mmol, 57% yield). LCMS RT=1.28 min, ES+ve m/z 813 [M+H]⁺.

2-(2-(2-(4-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)piperazin-1-yl)ethoxy)ethoxy)acetic acid

A solution of tert-butyl 2-(2-(2-(4-(4-(6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophene-3-carbonyl)phenyl)piperazin-1-yl)ethoxy)ethoxy)acetate (80 mg, 0.098 mmol) in a mixture of DMF (2 mL) and water (0.2 mL) was treated with ammonium formate (62 mg, 0.98 mmol) and palladium on carbon (10% degussa type) (18 mg, 0.017 mmol) and stirred at 50° C. for 1 hour. The cooled mixture was filtered and evaporated to dryness. The residue was treated with TFA (5 mL), stirred for 1 hour and then evaporated to dryness. The product was subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (34 mg, 0.059 mmol, 60% yield). LCMS RT=0.67 min, ES+ve m/z 577 [M+H]⁺.

Example 24 (2S,4R)-4-Hydroxy-1-((S)-2-(2-(2-(2-(4-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)piperazin-1-yl)ethoxy)ethoxy)acetamido)-3,3-dimethylbutanoyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide

A mixture of 2-(2-(2-(4-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)piperazin-1-yl)ethoxy)ethoxy)acetic acid (25 mg, 0.036 mmol) and (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (26 mg, 0.055 mmol) in DMF (0.7 mL) was treated with DIPEA (0.045 mL, 0.26 mmol) and then with HATU (17 mg, 0.044 mmol) and stirred at ambient temperature for 15 minutes. The product was subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (12 mg, 0.012 mmol, 33% yield). LCMS RT=0.84 min, ES+ve m/z 989 [M+H]⁺.

(6-(Benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophen-3-yl)(4-(2-(4-(2-hydroxyethyl)piperazin-1-yl)ethoxy)phenyl)methanone

Under an atmosphere of nitrogen, a solution of (6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophen-3-yl)(4-fluorophenyl)methanone (300 mg, 0.55 mmol) in DMF (1 mL) was treated with 2,2′-(piperazine-1,4-diyl)diethanol (384 mg, 2.2 mmol) and then with sodium hydride (60% in mineral oil) (44 mg, 1.1 mmol) and the mixture was heated at 50° C. overnight. The cooled mixture was treated with 4M HCl in 1,4-dioxane (0.1 mL) and then the product was subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (177 mg, 0.25 mmol, 46% yield). LCMS RT=1.21 min, ES+ve m/z 699 [M+H]⁺.

tert-Butyl 2-(2-(4-(2-(4-(6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethyl)piperazin-1-yl)ethoxy)acetate

Under an atmosphere of nitrogen, a solution of (6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophen-3-yl)(4-(2-(4-(2-hydroxyethyl)piperazin-1-yl)ethoxy)phenyl)methanone (120 mg, 0.17 mmol) in DMF (3 mL) was treated with tert-butyl bromoacetate (0.051 mL, 0.34 mmol) and then with sodium hydride (60% in mineral oil) (28 mg, 0.69 mmol) and stirred at ambient temperature overnight. The mixture was treated with 5% aqueous ammonium chloride (20 mL) and extracted with dichloromethane (30 mL). The organic phase was evaporated to dryness and the product was subjected to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (88 mg, 0.11 mmol, 63% yield). LCMS RT=1.30 min, ES+ve m/z 813 [M+H]⁺.

2-(2-(4-(2-(4-(6-Hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethyl)piperazin-1-yl)ethoxy)acetic acid

A solution of tert-butyl 2-(2-(4-(2-(4-(6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethyl)piperazin-1-yl)ethoxy)acetate (80 mg, 0.098 mmol) in a mixture of DMF (2 mL) and water (150 μl) was treated with ammonium formate (62 mg, 0.98 mmol) and palladium on carbon (10% degussa type) (18 mg, 0.017 mmol) and stirred at 50° C. for 1 hour. The cooled mixture was filtered and the filtrate evaporated to dryness. The residue was treated with TFA (5 mL), stirred for 1 hour and then evaporated to dryness. The product was subjected to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (22 mg, 0.038 mmol, 39% yield). LCMS RT=0.67 min, ES+ve m/z 577 [M+H]⁺.

Example 25 (2S,4R)-4-Hydroxy-1-((S)-2-(2-(2-(4-(2-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethyl)piperazin-1-yl)ethoxy)acetamido)-3,3-dimethylbutanoyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide

A mixture of 2-(2-(4-(2-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethyl)piperazin-1-yl)ethoxy)acetic acid (25 mg, 0.036 mmol) and (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (26 mg, 0.055 mmol) in DMF (0.7 mL) was treated with DIPEA (0.045 mL, 0.26 mmol) and then with HATU (17 mg, 0.044 mmol) and stirred at ambient temperature for 15 minutes. The product was subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to the title compound (18 mg, 0.018 mmol, 50% yield). LCMS RT=0.91 min, ES+ve m/z 989 [M+H]⁺.

tert-Butyl 4-(1-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)piperidin-4-yl)piperazine-1-carboxylate

A solution of (4-fluorophenyl)(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)methanone (300 mg, 0.82 mmol) in N-methyl-2-pyrrolidone (4 mL) was sealed and heated in a Biotage “Initiator” microwave at 140° C. for 90 min. The product was subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (221 mg, 0.36 mmol, 44% yield). LCMS RT=0.81 min, ES+ve m/z 614 [M+H]⁺.

(6-Hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)(4-(4-(piperazin-1-yl)piperidin-1-yl)phenyl)methanone, hydrochloride

tert-Butyl 4-(1-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)piperidin-4-yl)piperazine-1-carboxylate (221 mg, 0.36 mmol) was dissolved in trifluoroacetic acid (4 mL). After 30 minutes the solution was evaporated to dryness, the residue was taken up in THF (10 mL), treated with 4M HCl in 1,4-dioxane (2 mL) and evaporated to dryness to afford the title compound (174 mg, 0.32 mmol, 89% yield). LCMS RT=0.64 min, ES+ve m/z 514 [M+H]⁺.

tert-Butyl 2-(4-(1-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)piperidin-4-yl)piperazin-1-yl)acetate

A solution of (6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)(4-(4-(piperazin-1-yl)piperidin-1-yl)phenyl)methanone (300 mg, 0.58 mmol) in DMF (1 mL) was treated with sodium bicarbonate (245 mg, 2.9 mmol) and tert-butyl bromoacetate (0.129 mL, 0.88 mmol) and the mixture was stirred at ambient temperature for 3 days. The product was subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (160 mg, 0.26 mmol, 44% yield). LCMS RT=0.79 min, ES+ve m/z 628 [M+H]⁺.

2-(4-(1-(4-(6-Hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)piperidin-4-yl)piperazin-1-yl)acetic acid, 3 hydrochloride

A solution of tert-butyl 2-(4-(1-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)piperidin-4-yl)piperazin-1-yl)acetate (160 mg, 0.26 mmol) in THF (10 mL) and treated with 25% aqueous HCl (5 mL) and after 1 hour blown to dryness in a stream of nitrogen to afford the title compound (164 mg, 0.24 mmol, 92% yield). LCMS RT=0.65 min, ES+ve m/z 572 [M+H]⁺.

Example 26 (2S,4R)-4-hydroxy-1-((S)-2-(2-(4-(1-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)piperidin-4-yl)piperazin-1-yl)acetamido)-3,3-dimethylbutanoyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide

A mixture of 2-(4-(1-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)piperidin-4-yl)piperazin-1-yl)acetic acid, 3 hydrochloride (37 mg, 0.054 mmol) and (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (38 mg, 0.081 mmol) in DMF (0.7 mL) was treated with DIPEA (0.066 mL, 0.38 mmol) and then with HATU (25 mg, 0.065 mmol) and stirred at ambient temperature for 15 minutes. The product was subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (22 mg, 0.022 mmol, 41% yield). LCMS RT=0.83 min, ES+ve m/z 984 [M+H]⁺.

tert-Butyl 9-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)-3,9-diazaspiro[5.5]undecane-3-carboxylate

A mixture of (4-fluorophenyl)(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)methanone (200 mg, 0.55 mmol) and tert-butyl 3,9-diazaspiro[5.5]undecane-3-carboxylate (commercially available from for example Matrix Scientific) (279 mg, 1.1 mmol) was heated in a Biotage microwave at 130° C. for 4 hours. The reaction mixture was cooled to room temperature, diluted with DMF (3 mL), and was then subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (215 mg, 0.36 mmol, 65% yield). LCMS RT=1.22 min, ES+ve m/z 599.5 [M+H]⁺.

(4-(3,9-Diazaspiro[5.5]undecan-3-yl)phenyl)(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)methanone, 2 hydrochloride

HCl in dioxane (4 M, 1.5 mL, 6.0 mmol) was added to a solution of tert-butyl 9-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)-3,9-diazaspiro[5.5]undecane-3-carboxylate (215 mg, 0.36 mmol) in a mixture of DCM (1 mL) and MeOH (0.5 mL), and the mixture was stirred at room temperature for 18 hours. The solvent was removed under reduced to afford the title compound (190 mg, 0.33 mmol, 93% yield). LCMS RT=0.72 min, ES+ve m/z 499.1 [M+H]⁺.

tert-Butyl 2-(9-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)-3,9-diazaspiro[5.5]undecan-3-yl)acetate, formic acid salt

A vial was charged with (4-(3,9-diazaspiro[5.5]undecan-3-yl)phenyl)(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)methanone, 2 hydrochloride (43 mg, 0.075 mmol), tert-butyl 2-bromoacetate (commercially available from for example Aldrich) (0.013 mL, 0.09 mmol) and sodium bicarbonate (32 mg, 0.38 mmol) in DMF (0.6 mL). The vial was sealed and the reaction was heated at 50° C. for 2 hours. The reaction was cooled to room temperature, filtered and was subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (37 mg, 0.056 mmol, 75% yield). LCMS RT=0.84 min, ES+ve m/z 613.4 [M+H]⁺.

2-(9-(4-(6-Hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)-3,9-diazaspiro[5.5]undecan-3-yl)acetic acid, 2 hydrochloride

tert-Butyl 2-(9-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)-3,9-diazaspiro[5.5]undecan-3-yl)acetate, formic acid salt (37 mg, 0.056 mmol) was treated cautiously with TFA (0.5 mL) and the mixture was stirred at room temperature for 30 min. The reaction mixture was concentrated, treated with HCl in dioxane (4M, 2 mL), and was stirred at room temperature for 30 min. The solvent was removed under reduced to afford the title compound (35 mg, 0.056 mmol, 100% yield). LCMS RT=0.74 min, ES+ve m/z 557.1 [M+H]⁺.

Example 27 (2S,4R)-4-Hydroxy-1-((S)-2-(2-(9-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)-3,9-diazaspiro[5.5]undecan-3-yl)acetamido)-3,3-dimethylbutanoyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, formic acid salt

HATU (24 mg, 0.062 mmol) was added to a mixture of (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (33 mg, 0.071 mmol), 2-(9-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)-3,9-diazaspiro[5.5]undecan-3-yl)acetic acid, 2 hydrochloride (30 mg, 0.048 mmol) and DIPEA (0.083 mL, 0.476 mmol) in DMF (0.6 mL). The reaction was stirred at room temperature for 30 min, and was then subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (20 mg, 0.02 mmol, 41% yield). LCMS RT=0.85 min, ES+ve m/z 969.4 [M+H]⁺.

tert-Butyl 2-(2-(9-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)-3,9-diazaspiro[5.5]undecan-3-yl)ethoxy)acetate, formic acid salt

A vial was charged with (4-(3,9-diazaspiro[5.5]undecan-3-yl)phenyl)(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)methanone, 2 hydrochloride (43 mg, 0.075 mmol), tert-butyl 2-(2-(tosyloxy)ethoxy)acetate (0.028 mL, 0.11 mmol) and sodium bicarbonate (32 mg, 0.38 mmol) in DMF (0.6 mL). The vial was sealed and the reaction was heated at 60° C. for 20 hours. The reaction was cooled to room temperature, filtered and was subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (34 mg, 0.048 mmol, 64% yield). LCMS RT=0.88 min, ES+ve m/z 657.4 [M+H]⁺.

2-(2-(9-(4-(6-Hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)-3,9-diazaspiro[5.5]undecan-3-yl)ethoxy)acetic acid, 2 hydrochloride

tert-Butyl 2-(2-(9-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)-3,9-diazaspiro[5.5]undecan-3-yl)ethoxy)acetate, formic acid salt (34 mg, 0.048 mmol) was treated cautiously with TFA (0.5 mL) and the mixture was stirred at room temperature for 10 min. The reaction mixture was concentrated, treated with HCl in dioxane (4M, 2 mL), and was stirred at room temperature for 30 min. The solvent was removed under reduced to afford the title compound (32 mg, 0.048 mmol, 100% yield). LCMS RT=0.77 min, ES+ve m/z 601.3 [M+H]⁺.

Example 28 (2S,4R)-4-Hydroxy-1-((S)-2-(2-(2-(9-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)-3,9-diazaspiro[5.5]undecan-3-yl)ethoxy)acetamido)-3,3-dimethylbutanoyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, 2 formic acid salt

HATU (13 mg, 0.035 mmol) was added to a mixture of (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (16 mg, 0.035 mmol), 2-(2-(9-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)-3,9-diazaspiro[5.5]undecan-3-yl)ethoxy)acetic acid, 2 hydrochloride (18 mg, 0.027 mmol) and DIPEA (0.047 mL, 0.27 mmol) in DMF (0.6 mL). The reaction was stirred at room temperature for 30 min, and was then subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (3.3 mg, 3.0 μmol, 11% yield), LCMS RT=0.84 min, ES+ve m/z 1013.5 [M+H]⁺, 507.7 [M/2+H]⁺.

Example 29 (2S,4R)-1-((S)-2-(tert-Butyl)-17-(4-(2-(4-hydroxyphenyl)-6-methoxybenzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12,15-tetraoxa-3-azaheptadecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide

A mixture of 14-(4-(6-hydroxy-2-(4-methoxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-3,6,9,12-tetraoxatetradecan-1-oic acid (20 mg, 0.033 mmol) and (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide, hydrochloride (23 mg, 0.049 mmol) in DMF (0.7 mL) was treated with DIPEA (0.023 mL, 0.13 mmol) and then with HATU (15 mg, 0.039 mmol) and stirred at ambient temperature for 15 minutes. The product was subjected directly to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (12 mg, 0.014 mmol, 36% yield). LCMS RT=1.14 min, ES+ve m/z 1023.5 [M+H]⁺.

3-Bromo-6-methoxy-2-(4-methoxyphenyl)benzo[b]thiophene can be prepared according to the process described by Palkowitz, Alan David, U.S. Pat. No. 5,492,922A.

3-Bromo-2-(4-hydroxyphenyl)benzo[b]thiophen-6-ol

BBr₃ (commercially available from for example Aldrich) (2.274 mL, 24.05 mmol) was added to a suspension of 3-bromo-6-methoxy-2-(4-methoxyphenyl)benzo[b]thiophene (2.8 g, 8.02 mmol) in dichloromethane (100 mL) stirring at 0° C. under an atmosphere of nitrogen. The reaction was stirred for 2 hours at that temperature. Water (100 mL) was carefully added and the product was extracted with ethyl acetate (200 mL). The aqueous layer was washed with ethyl acetate (200 mL) and the organic fractions were then combined, washed with brine (2×200 mL), dried with MgSO₄ and concentrated under reduced pressure to afford the title compound (2.34 g, 7.29 mmol, 91% yield) as a beige solid. LCMS RT=0.97 min, ES+ve m/z 320.5/322.1 [M+H]⁺.

6-(Benzyloxy)-2-(4-(benzyloxy)phenyl)-3-bromobenzo[b]thiophene 1-oxide

3-Bromo-2-(4-hydroxyphenyl)benzo[b]thiophen-6-ol (2.12 g, 6.60 mmol) was dissolved in N,N-dimethylformamide (50 mL) and stirred at 0° C. NaH, 60% w/w in mineral oil (0.792 g, 19.80 mmol) was added and the reaction was stirred at 0° C. for 10 minutes. (Bromomethyl)benzene (commercially available from for example Aldrich) (2.4 mL, 20.18 mmol) was added and the reaction stirred at room temperature overnight. A saturated solution of NH₄Cl (10 mL) was added cautiously followed by water (100 ml). The product was extracted with ethyl acetate (200 mL). The organic phase was washed with brine (100 mL) and concentrated. The intermediate was purified by chromatography on silica using a gradient elution from 0% to 50% ethyl acetate in cyclohexane. The appropriate fraction was evaporated to give the required crude intermediate (2 g). To a solution of the obtained compound (2 g) in dichloromethane (20 mL) was added trifluoroacetic acid (20 mL). The reaction was cool to 0° C. and after 5 minutes of stirring, H₂O₂, 30% w/w in water (0.489 mL, 4.79 mmol) was added. The resulting mixture was stirred at 0° C. for 30 minutes and at room temperature for 1 h. Solid sodium bisulfite (0.265 g) was added cautiously to the dark solution followed by 3 mL of water. The mixture was stirred vigorously for 15 minutes and then concentrated in vacuo. The residue was partitioned between dichloromethane (80 mL) and saturated NaHCO₃ solution (80 mL). The layers were separated, and the organic phase was extracted with saturated NaHCO₃ solution. The organic phase was then dried using a hydrophobic frit and concentrated in vacuo. The obtained solid was triturated with Et₂O/EtOAc and the brown solid was filtrated to afford the title compound (780 mg, 1.507 mmol, 23% yield). LCMS RT=1.47 min, ES+ve m/z 517.2/519.1 [M+H]⁺.

6-(Benzyloxy)-2-(4-(benzyloxy)phenyl)-3-(4-(tert-butoxy)phenoxy)benzo[b]thiophene

4-(tert-Butoxy)phenol (302 mg, 1.815 mmol) was dissolved in N,N-dimethylformamide (15 mL). NaH, 60% w/w in mineral oil (132 mg, 3.30 mmol) was added slowly followed by 6-(benzyloxy)-2-(4-(benzyloxy)phenyl)-3-bromobenzo[b]thiophene 1-oxide (854 mg, 1.650 mmol). The reaction mixture was stirred at room temperature for 1.5 h. Water (300 mL) was added and the product was extracted with EtOAc (300 mL). 2M aqueous HCl was added until the pH of aqueous phase was 1 and the aqueous phase was extracted with EtOAc (400 mL). The combined organic extracts were washed with brine (300 mL), dried using a hydrophobic frit and concentrated under reduced pressure to give the crude intermediate (1.08 g) as a brown solid. LiAlH₄ in THF (1M, 4.48 mL, 4.48 mmol) was added to a mixture of the obtained intermediate (1.08 g) in tetrahydrofuran (20 mL). The reaction was stirred at ambient temperature for 1.5 h. Aqueous NaOH (50%, 15 mL) was carefully added and the mixture was partitioned between EtOAc (100 mL) and water (100 mL). The aqueous phase was further extracted with EtOAc (3×100 mL). The organic extracts were combined, dried using a hydrophobic frit and concentrated under reduced pressure. The product was purified by chromatography on silica using a gradient elution from 0% to 50% dichloromethane in cyclohexane followed by a 100% dichloromethane wash of the column to afford the title compound (440 mg, 0.75 mmol, 45% yield). LCMS RT=1.71 min, ES+ve m/z 587.3 [M+H]⁺.

4-((6-(Benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophen-3-yl)oxy)phenol

6-(Benzyloxy)-2-(4-(benzyloxy)phenyl)-3-(4-(tert-butoxy) phenoxy)benzo[13]thiophene (440 mg, 0.750 mmol) was dissolved in 1,4-dioxane (20 mL). HCl in dioxane (4M, 1.875 mL, 7.50 mmol) was added and the reaction was stirred at 40° C. for 60 h. A further aliquot of HCl in dioxane (4M, 1.875 mL, 7.50 mmol) was added and the reaction was stirred at 60° C. for 4 h. The reaction mixture was evaporated under reduced pressure to afford the title compound (405 mg, 0.763 mmol, >100% yield). LCMS RT=1.53 min, ES+ve m/z 531.2 [M+H]⁺

tert-Butyl 2-(2-(2-(2-(4-((6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)ethoxy)ethoxy)ethoxy)acetate

A mixture of 4-((6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophen-3-yl)oxy)phenol (4.03 g, 7.59 mmol), tert-butyl 2-(2-(2-(2-(tosyloxy)ethoxy)ethoxy)ethoxy)acetate (5.40 g, 12.91 mmol), K₂CO₃ (316 mg, 2.290 mmol) in N,N-dimethylformamide (60 mL) was heated at 85° C. for 48 h. The reaction was cooled to room temperature and partitioned between EtOAc (600 mL) and water (600 mL). The organic extract was dried with MgSO₄, filtered using an hydrophobic frit and concentrated under reduced pressure. The product was purified by chromatography on silica using a gradient elution from 0 to 50% TBME in cyclohexane to afford the title compound (2 g, 2.57 mmol, 34% yield) as a brown oil. LCMS RT=1.64 min, ES+ve m/z 799.6 [M+Na]⁺

tert-Butyl 2-(2-(2-(2-(4-((6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)ethoxy)ethoxy)ethoxy)acetate

A mixture of tert-butyl 2-(2-(2-(2-(4-((6-(benzyloxy)-2-(4-(benzyloxy)phenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)ethoxy)ethoxy)ethoxy)acetate (2 g, 2.57 mmol) and palladium on carbon (10% w/w, 1.096 g, 1.030 mmol) in ethyl acetate (100 mL) and HCl in EtOH (1%, 15.67 mL, 5.16 mmol) was stirred at room temperature overnight under an atmosphere of hydrogen. The reaction mixture was filtered on celite and the filtrate was concentrated under reduced pressure. The resulting oil was evaporated under high vacuum overnight to afford the title compound (1.478 g, 2.477 mmol, 96% yield). LCMS RT=1.12 min, ES+ve m/z 619.3 [M+Na]⁺.

Example 1 Alternative Synthesis (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-((6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide

tert-Butyl 2-(2-(2-(2-(4-((6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)ethoxy)ethoxy)ethoxy)acetate (100 mg, 0.168 mmol) was dissolved in 1,4-dioxane (2 mL). HCl in dioxane (4M, 0.210 mL, 0.840 mmol) was added and the reaction mixture was stirred at 40° C. for 3 h. A further aliquot of HCl in dioxane (4M, 0.210 mL, 0.840 mmol) was added and the reaction mixture was stirred at 40° C. overnight. The reaction mixture was concentrated under reduced pressure. The residue was dissolved in acetonitrile and concentrated under reduced pressure (this process was done twice) to give the carboxylic acid intermediate (80 mg). HATU (77 mg, 0.203 mmol) was added to a solution of the obtained intermediate (80 mg), DIPEA (0.2 mL, 1.145 mmol) and (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide (94 mg, 0.218 mmol) in N,N-dimethylformamide (1.5 mL). The reaction mixture was stirred for 45 min at room temperature. The crude mixture was directly subjected to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (50 mg, 0.052 mmol, 31% yield). LCMS RT=1.04 min, ES+ve m/z 953.7 [M+H]⁺.

(2S,4R)—N-(4-Chlorobenzyl)-4-hydroxypyrrolidine-2-carboxamide, hydrochloride

HATU (1676 mg, 4.41 mmol) was added portionwise to a solution of (2S,4R)-1-(tert-butoxycarbonyl)-4-hydroxypyrrolidine-2-carboxylic acid (commercially available from for example Aldrich) (1.019 g, 4.41 mmol), (4-chlorophenyl)methanamine (commercially available from for example Aldrich) (520 mg, 3.67 mmol) and DIPEA (1.924 mL, 11.02 mmol) in DMF (20 mL). The reaction was stirred at room temperature for 3 h. The reaction mixture was partitioned between EtOAc (100 mL) and water (100 mL). The aqueous phase was back extracted with EtOAc (100 mL) and the organic phase was dried with MgSO₄. The combined organic extracts were dried using a hydrophobic frit and concentrated under reduced pressure. The residue was purified by chromatography on silica using a gradient elution from 0 to 50% MeOH in TBME to afford the required intermediate (1.053 g). The obtained compound was dissolved in HCl in dioxane (4M, 10 mL, 40 mmol) and the solution was stirred for 30 min. MeOH (10 mL) was added to solubilise the white suspension and the reaction mixture was stirred for further 30 min. The solvent was concentrated under reduced pressure to give a white solid. MeOH was added and the product was concentrated under reduced pressure (this process was done twice) to afford the title compound (895 mg, 3.07 mmol, 84% yield) as a white solid. LCMS RT=0.54 min, ES+ve m/z 255.2 [M+H]⁺.

(2S,4R)-1-((S)-2-Amino-3,3-dimethylbutanoyl)-N-(4-chlorobenzyl)-4-hydroxypyrrolidine-2-carboxamide, hydrochloride

HATU (1.603 g, 4.22 mmol) was added portionwise to a solution of (S)-2-((tert-butoxycarbonyl)amino)-3,3-dimethylbutanoic acid (975 mg, 4.22 mmol), (2S,4R)—N-(4-chlorobenzyl)-4-hydroxypyrrolidine-2-carboxamide, hydrochloride (895 mg, 3.07 mmol) and DIPEA (1.841 mL, 10.54 mmol) in DMF (40 mL). The reaction was stirred for 45 min at room temperature. The reaction mixture was partitioned between EtOAc (200 mL) and water (200 mL). The aqueous phase was back extracted with EtOAc (200 mL) and the combined organic phases were washed with brine (200 mL). The organic phase was dried using a hydrophobic frit and concentrated under reduced pressure. The residue was purified by chromatography on silica using a gradient elution from 0 to 25% MeOH in methyl tert-butyl ether to afford the required intermediate (500 mg). The obtained compound was stirred in HCl in dioxane (4M, 10 mL, 40 mmol) at room temperature for 1 h. The reaction mixture was concentrated under reduced pressure. The residue was dried under high vacuum for 48 h to afford the title compound (396 mg, 0.979 mmol, 32% yield), as a white solid. LCMS RT=0.63 min, ES+ve m/z 368.2 [M+H]⁺.

Example 30 (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-((6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-N-(4-chlorobenzyl)-4-hydroxypyrrolidine-2-carboxamide

tert-Butyl 2-(2-(2-(2-(4-((6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)ethoxy)ethoxy)ethoxy)acetate (100 mg, 0.168 mmol) was dissolved in HCl in dioxane (4M, 2 mL, 8 mmol). The reaction was stirred 3 h. The reaction mixture was concentrated under reduced pressure. The residue was dissolved in acetonitrile then concentrated under reduced pressure (this process was done twice) to give the carboxylic acid intermediate (80 mg). HATU (70 mg, 0.184 mmol) was added to a solution of the obtained intermediate (80 mg), DIPEA (0.2 mL, 1.145 mmol) and (2S,4R)-1-((S)-2-amino-3,3-dimethylbutanoyl)-N-(4-chlorobenzyl)-4-hydroxypyrrolidine-2-carboxamide, hydrochloride (70 mg, 0.173 mmol) in DMF (1.5 mL). The mixture was stirred at room temperature overnight. The crude mixture was directly subjected to purification by mass-directed automated preparative HPLC (formic acid modifier) to afford the title compound (50 mg, 0.056 mmol, 34% yield). LCMS RT=1.11 min, ES+ve m/z 889.0 [M−H]⁻.

Estrogen Receptor Alpha (ERa) Degradation and Cell Count Imaging Assay

Compounds were assessed for ERa degradation and cell count effects in an MCF-7 cell line using high content imaging. 50 ul of MCF-7 cell suspension in media was dispensed to each well of black walled, clear bottomed, PDL-coated plates, containing a defined concentration of test compound dissolved in DMSO covering concentration range from 0.03 uM to 30 uM. Cells were incubated in the presence of compound for 24 hours at 37° C., 5% CO₂ before cells were fixed. After incubation with the fixative solution (4% formaldehyde) the wells were aspirated and a solution containing detergent was added to permeabilise the cells followed by addition of blocking solution containing 1% BSA (bovine serum albumin) to block the non-specific binding sites. After a further incubation for 1 hour this solution was aspirated from the wells and the ERa specific antibody diluted in blocking solution at concentration 1 ug/ml (anti ERa, cat no sc-543, Santa Cruz) was added. Following incubation with the antibody for 2 hours the cells were washed with a PBS-based solution before addition of a secondary anti rabbit fluorescently-labelled Alexa Fluor 488 goat antibody at 2 ug/ml concentration (cat no11008, Invitrogen) and a nuclear staining dye Hoechst33342 at 1 ug/ml concentration (cat no H3570, invitrogen). Following a further incubation for 1 hour the cells were again washed with the PBS-based solution. The plates were then imaged and the intensity of ERa staining in the nucleus and cell count measured. ERa degradation activity was expressed relative to DMSO, giving 0% degradation, and an in-house degrader molecule classified as giving 100% activity. Cell count reduction was expressed relative to DMSO, classified as 0% reduction.

Examples showed evidence of ERa degradation in this assay relative to the DMSO control at 1 uM concentration. 

What is claimed is:
 1. A compound of formula (I):

Wherein R¹ is OH, OC₁₋₃alkyl, halogen, H R² is OH, OC₁₋₃alkyl X is O, CO L is a linking group comprising a length of 8-16 atoms in shortest length R₃ is straight or branched chain C₁₋₆alkyl, C₃₋₆ cycloalkyl R₄ is 4-methylthiazol-5-yl, oxazol-5-yl, halo or a pharmaceutically acceptable salt thereof.
 2. A compound or a pharmaceutically acceptable salt thereof according to claim 1 wherein R₄ is 4-methylthiazol-5-yl, oxazol-5-yl.
 3. A compound or a pharmaceutically acceptable salt thereof according to claim 2 wherein R₄ is 4 methylthiazol-5-yl.
 4. A compound or a pharmaceutically acceptable salt thereof according to claim 1 wherein R₄ is chloro.
 5. A compound or a pharmaceutically acceptable salt thereof according to claim 2 wherein R₄ is oxazol-5-yl.
 6. A compound or a pharmaceutically acceptable salt thereof according to claim 1 where in R¹ is OH, F, Br, OCH₃ or H.
 7. A compound or a pharmaceutically acceptable salt thereof according to claim 6 wherein R¹ is OH.
 8. A compound or a pharmaceutically acceptable salt thereof according to claim 1 wherein R² is OH or OCH₃.
 9. A compound or a pharmaceutically acceptable salt thereof according to claim 8 wherein R² is OH.
 10. A compound or a pharmaceutically acceptable salt thereof according to claim 1 wherein the linker group is a straight chain alkylene group of 8-16 carbon atoms wherein one or more carbon atoms are replaced by a group each independently selected from —O—, —NH—, —N(CH₃)—,


11. A compound or a pharmaceutically acceptable salt thereof according to claim 10 wherein the linker group is of formula (ii) —(R⁵CH₂CH₂)_(X)OCH₂   (ii) wherein each R⁵ is independently selected from —O—, —NH—, —N(CH₃)— or

and x is 2-4.
 12. A compound or a pharmaceutically acceptable salt thereof according to claim 1 wherein the linker is selected from (OCH₂CH₂)₄OCH₂ (OCH₂CH₂)₃OCH₂ (OCH₂CH₂)₂OCH₂

OCH₂CH₂N(CH₃)CH₂CH₂OCH₂CH₂OCH₂ OCH₂CH₂N(CH₃)(CH₂)₃(OCH₂CH₂)₂OCH₂


13. A compound of formula (I) according to claim 1 which is selected from the group consisting of (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-((6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-4-Hydroxy-1-((S)-14-(4-((6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)-2-isopropyl-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-((6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(oxazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-((2-(4-hydroxyphenyl)-6-methoxybenzo[b]thiophen-3-yl)oxy)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-((6-hydroxy-2-phenylbenzo[b]thiophen-3-yl)oxy)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-1-((S)-14-(4-((2-(4-Bromophenyl)-6-hydroxybenzo[b]thiophen-3-yl)oxy)phenoxy)-2-(tert-butyl)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-((2-(4-fluorophenyl)-6-hydroxybenzo[b]thiophen-3-yl)oxy)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-4-Hydroxy-1-((S)-14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-2-methyl-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-1-((S)-2-Ethyl-14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-4-Hydroxy-1-((S)-14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-2-isopropyl-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-1-((S)-2-Cyclopropyl-14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-1-((S)-2-Cyclopentyl-14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-4-Hydroxy-1-((S)-14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-2-isobutyl-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-4-Hydroxy-1-((S)-17-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-2-isopropyl-4-oxo-6,9,12,15-tetraoxa-3-azaheptadecan-1-oyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-1-((S)-2-(tert-Butyl)-17-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12,15-tetraoxa-3-azaheptadecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-(2-(4-Hydroxyphenyl)-6-methoxybenzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-(6-hydroxy-2-(4-methoxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-1-((S)-2-(tert-Butyl)-17-(4-(6-hydroxy-2-(4-methoxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12,15-tetraoxa-3-azaheptadecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-4-hydroxy-N-(4-(oxazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-4-Hydroxy-1-((S)-2-(2-(2-(2-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethoxy)ethoxy)acetamido)-3, 3-dimethylbutanoyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-12-methyl-4-oxo-6,9-dioxa-3,12-diazatetradecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-1-((S)-2-(tert-Butyl)-18-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)-16-methyl-4-oxo-6,9,12-trioxa-3,16-diazaoctadecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-4-Hydroxy-1-((S)-2-(2-(2-(2-(4-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)piperazin-1-yl)ethoxy)ethoxy)acetamido)-3,3-dimethylbutanoyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-4-Hydroxy-1-((S)-2-(2-(2-(4-(2-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenoxy)ethyl)piperazin-1-yl)ethoxy)acetamido)-3,3-dimethylbutanoyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-4-Hydroxy-1-((S)-2-(2-(4-(1-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)piperidin-4-yl)piperazin-1-yl)acetamido)-3,3-dimethylbutanoyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-4-Hydroxy-1-((S)-2-(2-(9-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)-3,9-diazaspiro[5.5]undecan-3-yl)acetamido)-3,3-dimethylbutanoyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-4-Hydroxy-1-((S)-2-(2-(2-(9-(4-(6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophene-3-carbonyl)phenyl)-3,9-diazaspiro[5.5]undecan-3-yl)ethoxy)acetamido)-3,3-dimethylbutanoyl)-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-1-((S)-2-(tert-Butyl)-17-(4-(2-(4-hydroxyphenyl)-6-methoxybenzo[b]thiophene-3-carbonyl)phenoxy)-4-oxo-6,9,12,15-tetraoxa-3-azaheptadecan-1-oyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide; (2S,4R)-1-((S)-2-(tert-Butyl)-14-(4-((6-hydroxy-2-(4-hydroxyphenyl)benzo[b]thiophen-3-yl)oxy)phenoxy)-4-oxo-6,9,12-trioxa-3-azatetradecan-1-oyl)-N-(4-chlorobenzyl)-4-hydroxypyrrolidine-2-carboxamide; and pharmaceutically acceptable salts thereof.
 14. (canceled)
 15. A pharmaceutical composition comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof according to claim 1 and one or more of pharmaceutically acceptable carriers, diluents and excipients.
 16. A method of treating diseases and conditions mediated by the estrogen receptor in a subject comprising administering a therapeutically effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof according to claim
 1. 17. (canceled)
 18. A combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof according to claim 1 and at least one further therapeutic agent.
 19. A combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof according to claim 1 and at least one further therapeutic agent for use in therapy, particularly for treating diseases and conditions mediated by the estrogen receptor.
 20. (canceled)
 21. A method of treating diseases and conditions mediated by the estrogen receptor comprising administering to a human in need thereof a therapeutically effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof, according to claim
 1. 22. (canceled)
 23. A combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof according to claim 1 and at least one anti-neoplastic agent. 24-26. (canceled)
 27. A method of treating diseases and conditions mediated by the estrogen receptor, comprising administering to a human in need thereof a therapeutically effective amount of a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof according to claim 1 and at least one anti-neoplastic agent.
 28. A pharmaceutical composition comprising a combination comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof according to claim 1 and at least one further therapeutic agent, particularly at least one anti-neoplastic agent and one or more of pharmaceutically acceptable carriers, diluents and excipients.
 29. A method of treating breast cancer comprising administering to human in need thereof, a therapeutically effect amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof according to claim
 1. 30. A method of degrading the estrogen receptor comprising administration comprising administering to a human in need thereof a therapeutically effective amount of a compound of Formula (I) according to claim 1 or a pharmaceutically acceptable salt thereof. 